Thailand has declared martial law  in eight districts on the frontier with Cambodia amid border clashes, citing "Cambodia's use of force to enter Thai territory", media reports said.

Both countries exchanged heavy artillery for the second consecutive day, marking the worst escalation of tension between the neighbours in more than a decade.

The ongoing clash has left 15 people dead.

Thailand's Second Army Region reported clashes from before dawn in Ubon Ratchathani and Surin provinces and said Cambodia had used artillery and Russian-made BM-21 rocket systems, reported Bangkok Post.

More than 138,000 people have been evacuated from Thailand's border regions, its health ministry said, reporting 15 fatalities, 14 civilians and a soldier, with a further 46 wounded, including 15 troops.

Some 1,500 families in Cambodia's Oddar Meanchey province have been evacuated, BBC reported.

Malaysia appeals for peace

Meanwhile, Malaysian PM Anwar Ibrahim has appealed to the PMs of both nations to reach a ceasefire.

He wrote on Facebook: "This evening, I spoke with both the Prime Minister of the Kingdom of Cambodia, Hun Manet, and the Acting Prime Minister of the Kingdom of Thailand, Phumtham Wechayachai, expressing Malaysia’s deep concern over the escalation of tensions along their border."

He further said: "In our conversations, in Malaysia's capacity as ASEAN Chair for 2025, I appealed directly to both leaders for an immediate ceasefire to prevent further hostilities and to create space for peaceful dialogue and diplomatic resolution."