Three Thai soldiers were injured by a landmine near the Cambodian border on Saturday, the Thai army said, days after the Southeast Asian neighbours agreed to a detailed ceasefire halting last month's deadly five-day conflict.
One soldier lost a foot and two were injured after one of them stepped on a landmine while patrolling an area between Thailand's Sisaket and Cambodia's Preah Vihear provinces, the army said in a statement.
The soldiers were being treated at a hospital, it said.
Thailand said the incident occurred in an area of its territory recently cleared of landmines. The foreign ministry said Bangkok would lodge a complaint against Cambodia for violating a treaty, to which both are signatories, that bans the use of landmines and for infringing Thai sovereignty.
Cambodia rejected Thailand's accusation, saying that it had not freshly planted landmines.
The country is a "proud state party" to the Ottawa Convention against landmines and has cleared more than 1 million mines left from decades of war, the Cambodian Mine Action and Victim Assistance Authority said in a statement late on Saturday, adding that Thailand's accusations risked undermining the spirit of the ceasefire.
Bangkok and Phnom Penh have quarrelled for decades over undemarcated parts of their 817-km land border, which was first mapped by France in 1907 when Cambodia was its colony.
Saturday's incident is the third time in a few weeks that Thai soldiers have been injured by mines while patrolling along the border. Two previous incidents led to the downgrading of diplomatic relations and triggered the clashes.
The July 24-28 clashes, the worst fighting between the countries in more than a decade, involved exchanges of artillery fire and jet fighter sorties that killed at least 43 and left over 300,000 people displaced on both sides.
The fragile ceasefire has been holding since Thailand and Cambodia agreed on Thursday to let observers from the Association of Southeast Asian Nations inspect disputed border areas to ensure hostilities do not resume.
Bangkok accused Cambodia of planting landmines on the Thai side of the disputed border that injured soldiers on July 16 and July 23. Phnom Penh denied it had placed any new mines, saying the soldiers had veered off agreed routes and triggered old landmines left from its decades of war.

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