Suspected militants opened fire inside a mosque in Thailand's restive Muslim-majority south on Monday, killing at least 10 worshippers and wounding another 13, police said.
Up to five gunmen armed with assault rifles slipped through a back door into the mosque in Cho-ai-rong district in troubled Narathiwat province, a police official said.
"They opened fire indiscriminately at about 50 worshippers inside the mosque. Ten people were killed, including the local imam," the official said, adding that all the wounded were in a serious condition.
The attack happened during Muslim evening prayers at the mosque, police said.
Militants have stepped up attacks in southern Thailand in recent days, intensifying a five-year insurgency that has left more than 3,700 people dead and thousands more wounded.
A soldier was killed and eight others wounded by a bomb blast and militants shot dead a rubber-tapper in Narathiwat earlier on Monday.
On Sunday a huge bomb killed two people and destroyed several nearby buildings in the same province.