Story updated: Tuesday, April 23, 6.05am

At least 310 people are now reported to have died and 500 more have been injured following a series of explosions carried out by suicide bombers in Sri Lanka.

The terror attacks targeted well-known, high-end hotels during Sri Lanka’s holiday season and churches as congregations took part in Easter Sunday services. Hotels hit include the five-star Shangri-La, Kingsbury and Cinnamon Grand in Colombo.

The Sri Lankan government has accused local Jihadist group National Thowheed Jamath of carrying out the attacks and 24 arrests have been made.

However, Islamic State claimed it was behind the attacks through its own news agency on Tuesday (April 23).

Six initial blasts were followed by a further two attacks, with a ninth understood to have been foiled near the country’s main airport.

The BBC reported that 36 foreigners are known to have died but have yet to be identified. The UK government says at least eight Britons are among the dead, rising from a previously reported five. These included two with joint-US citizenship, Sri Lanka’s foreign ministry said.

A state of emergency came into effect at midnight local time on Monday.

The Sri Lankan government declared a curfew and shut down social media and instant messaging services across the country. SriLankan Airlines issued a statement to say those flying from Bandaranike International airport could still travel during the curfew but would need to produce air tickets and passports for security checks.

Abta urged British travellers to the country to follow latest travel advice from the Foreign and Commonwealth Office.

“The airport is still operating but there are increased security to measures in place,” Abta said.

“Some airlines are advising travellers to arrive early for check-in in order to allow time for security screening.

“There is a national curfew in place, but passengers are still able to travel to the airport, providing you have both a passport and ticket valid for travel that day.”

Customers due to travel to Sri Lanka imminently are also advised to check the FCO advice for updates.

“While the Foreign Office hasn’t put any travel restrictions to Sri Lanka in place, meaning normal booking conditions would apply if customers no longer wish to travel, travel companies’ policies will vary, depending on specific circumstances,” Abta added.

“Some Abta members are offering customers who are due to travel imminently the opportunity to change their booking, should they wish to do so. Travellers should contact their travel company to discuss their cancellation policies, and the options available.

“If you have booked all of your travel arrangements separately and you no longer wish to travel, you should speak to the individual companies about their cancellation policies.”

Latest FCO travel advice issued yesterday said: “Security has been stepped up across the island and there are ongoing security operations. These may continue for a number of days and the situation remains dynamic.

“Please follow the advice of local security authorities, hotel security staff and your tour company.

“The airport is operating, but with increased security checks and long queues for taxi pick-ups. Some airlines are advising their passengers to arrive early for check-in, in light of increased security screening. You should check with your airline about suggested check-in times.

“The Sri Lankan authorities have declared a nationwide curfew. You should limit movements until this has been lifted, following the instructions of the local authorities and your hotel/tour operator.

“The Sri Lankan authorities have confirmed that, if you need to catch a flight from Colombo airport, you are able to travel to the airport provided you have both passport and ticket valid for travel that day. They have also confirmed that arrangements have been put in place for arriving passengers.”

Britons directly affected by the attacks should “call the British High Commission in Colombo: +94 11 5390639, and select the emergency option from where you will be connected to one of our consular staff.”

The attacks were immediately condemned by international leaders and members of the UK travel industry, some of whom took to social media to provide updates on their customers and staff.

Andy Freeth, chief executive of tour operator If Only, said: “We’d like to advise our travel agent partners that our ground handling team and customers are all safe. Our thoughts are with the families affected by this awful tragedy.”

A statement from tour operator Kuoni said: “We can confirm that all Kuoni guests in Sri Lanka are safe. We are monitoring the situation closely alongside our team in Sri Lanka, Abta and the FCO.”

It added: “For guests who are in resort we are updating them on the situation and the latest travel advice as it evolves. We have advised those due to fly home today that transfers have been brought forward to allow for extra security checks at the airport, which remains open.

“If any agents have any concerns regarding their bookings please contact the Kuoni emergency number or email brad.bennetts@kuoni.co.uk or 07917058014.”

Tour operator Gold Medal said: “We are contacting all customers who are currently in resort to offer support and assistance. Should agents or customers need to contact us please call our out of hours team on 01772 550185.”

Lisa McAuley, managing director, Gold Medal and Travel 2, was among those to send messages of support.

She said: “Reflecting as we prepare to travel home from our family holiday; the devastation caused to others innocently caught up in the horror of the Sri Lanka attacks. Fortunate to have visited this beautiful island a few years ago and hold nothing but fond memories.”

Operator G Adventures confirmed on Monday that all its 116 travellers and staff across eight groups currently in Sri Lanka are “safe and accounted for”. All trips have been re-routed to avoid Colombo and travellers advised to contact their family and friends.

Founder Bruce Poon Tip said any attack on religious institutions is ‘an attack on all of us, regardless of faith’. He added: “We cannot allow this wave of division to further separate humanity.

“We must use this tragic loss to unite us. It’s my belief that compassion for all people, combined with an understanding of different backgrounds, religions and cultures, has the potential to be the fastest path to peace.”

Daniel Gathercole, managing director of tour operator First Class Holidays, said: “As a family we went to Sri Lanka last year and the people were amazing. It’s devastating to see what’s happened to a country already trying to get back on its feet after the tsunami. Very very sad.”

Wendy Wu Tours has one group tour in Sri Lanka and three tailor made bookings.

Global sales director John Warr reassured the trade that all guests in the region are accounted for.

He said: “We’re extremely thankful no one on our tour or any of our tailor made passengers were affected, and our ground staff are all safe and sound.

“When talking to members of the tour at the weekend they were all in good spirits and thankful for the immediate support Wendy Wu Tours offered and provided.

“Right now our thoughts and prayers go out to victims and the people of Sri Lanka.”

Richard Dixon, director of homeworking agency Holidaysplease, praised staff for their “outstanding commitment and service” updating customers in Sri Lanka and elsewhere in the world.

Nick Harding-McKay, managing director of London-based travel agency Travel Designers, tweeted: “My heart goes out to beautiful #SriLanka – what a horrible dark day for such an amazing place and wonderful people.”

Jeanne Lally, joint managing director of travel agency Travel Bureau, Gosforth, said she was “deeply saddened”, describing the attacks as an “abhorrent and despicable act of violence”.

Agents who wish to contact Cinnamon Hotels should call +94 11 2 437 437 for any guest related information and for Shangri-La hotel inquiries call +603 2025 4619.

Sri Lanka was named by Lonely Planet in October as the best country in the world to visit in 2019.

Tourist numbers hit a record of more than two million last year. The Sri Lanka Tourism Development Authority had hoped to see the level double by 2020.

Sri Lanka was due to mark ten years since the defeat of the separatist group Liberation Tigers of Tamil Eelam (LTTE) at the end of next month. Civil war between government armed forces and the militant group lasted 25 years and ended in 2009.