A Thai F-16 fighter jet bombed targets in Cambodia, both sides said, as weeks of tension over a border dispute escalated into clashes on Thursday that have killed at least 12 people, including 11 civilians.

Of the six F-16 fighter jets that Thailand readied to deploy along the disputed border, one of the aircraft fired into Cambodia and destroyed a military target, the Thai army said. Both countries accused each other of starting the clash early on Thursday.

“We have used air power against military targets as planned,” Thai army deputy spokesperson Richa Suksuwanon told reporters.

Thailand also closed its border with Cambodia.

Cambodia's defence ministry said the jets dropped two bombs on a road, and that it “strongly condemns the reckless and brutal military aggression of the Kingdom of Thailand against the sovereignty and territorial integrity of Cambodia”.

The skirmishes came after Thailand recalled its ambassador to Cambodia late on Wednesday and said it would expel Cambodia's envoy in Bangkok, after a second Thai soldier in the space of a week lost a limb to a landmine that Bangkok alleged had been laid recently in the disputed area.

Thailand's health minister said 11 civilians, including a child, and one soldier were killed in artillery shelling by Cambodian forces while 24 civilians and seven military personnel were wounded. There was no immediate word of casualties in Cambodia.

“The Thai Army condemns Cambodia for using weapons to attack civilians in Thailand. Thailand is ready to protect sovereignty and our people from inhumane action,” the country's military said in a statement.