Malaysia's Bernama state news agency said the two officers were killed in a mortar attack.

BBC: Sabah stand-off 'turns deadly' as clashes break out

"After the first attack, I stressed that the intruders must surrender themselves or the security forces will have to act, " he said in comments carried by Bernama.

BBC: Malaysia soldiers attack armed Filipino clan in Borneo

"I believe the people will make a wise decision, " Mr. Najib was quoted as saying by state-run news agency Bernama after he cast his ballot to defend his parliamentary seat in the eastern Pahang state.

WSJ: Malaysians Turn Out in Record Numbers in Tight, Historic Election

Malaysia Prime Minister Najib Razak, who has come under domestic pressure to bring an end to the incursion, said he had dispatched two additional battalions to Sabah, on Borneo island, Malaysia's Bernama state news agency reported.

BBC: Malaysia boosts Sabah security after Lahad Datu clashes

"I believe the people will make a wise decision, " Mr. Najib was quoted as saying by state-run news agency Bernama as saying after he cast his ballot to defend his parliamentary seat in the eastern Pahang state.

WSJ: Malaysians Turn Out in Large Numbers in Tight, Historic Election