Two people shot and killed two police officers in broad daylight in Las Vegas, before killing another person and then shooting themselves.

The incident began in a pizza cafe at 11.30am local time yesterday when a man and a woman shot at the two officers who were having lunch.

They then entered a Walmart shop nearby and shot one person dead, before committing suicide, the BBC reported.

Police say there are no other suspects in the shooting.

The woman shot her male companion before turning the gun on herself, Sheriff Doug Gillespie of the Las Vegas Metro Police Department said.

There was no obvious motive for the shootings.

However, eyewitnesses said the attackers shouted “This is a revolution” as they entered Cici Pizza and shot the police officers.

“I think in any case where people are ambushed and shot it’s upsetting to the public,” police spokesman Larry Hadfield told the Associated Press.

“We don’t know anything about the suspects yet and are trying to learn more.”