Thailand has recalled its ambassador to Cambodia and will expel Cambodia’s ambassador, the ruling Pheu Thai party said on Wednesday after a landmine incident that injured a Thai soldier along the disputed border between the two countries.

The Thai foreign ministry has lodged a formal protest with Cambodia, saying the landmines found in the area were newly deployed and had not been encountered during previous patrols, the party said on social media.

Thailand has downgraded diplomatic relations with Cambodia, it said.

Cambodia’s government did not immediately respond to a request for comment. Its government spokesperson referred Reuters to the foreign ministry. Thailand’s foreign ministry said it had yet to be informed of the decision to recall the Thai envoy and the plan to expel Cambodia’s ambassador.

The government has also ordered the closure of all border checkpoints under the jurisdiction of Thailand’s Second Army, the Pheu Thai party said.

“Tourists are strictly prohibited from entering these border areas,” it said.

In the landmine incident on Wednesday, the soldier sustained injuries and lost his right leg, the party said.

Earlier, Thailand accused Cambodia of placing landmines on the Thai side of the disputed border area after three soldiers were injured, but Phnom Penh denied the claim and said the soldiers had veered off agreed routes and triggered a mine left behind from decades of war.

Thai authorities said the soldiers were injured, with one losing a foot, by a landmine while on a patrol on 16 July on the Thai side of the disputed border area between Ubon Ratchathani and Cambodia’s Preah Vihear province.

Cambodia’s foreign ministry denied that new mines had been planted, and said in a statement on Monday night that the Thai soldiers deviated from agreed patrol routes into Cambodian territory and into areas that contain unexploded landmines.

The country is littered with landmines laid during decades of war.