Malaysian Prime Minister Najib Razak on Thursday rejected a ceasefire offered by a Philippine sultan after clashes between the sultan’s followers and Malaysian troops over a land claim in the eastern state of Sabah.

“They have to surrender their arms,” Mr. Najib said during a visit to the conflict zone in Lahad Datu town, 1,600 kilometres east of Kuala Lumpur. “They have to do it as soon as possible.” Mr. Najib said the operations against the Filipino militants will continue “for as long as it takes” or until “they lay down their arms unconditionally.” Mr. Najib’s office said his visit was to check on the logistics of the police and army operation hunting more than 200 followers of Sultan Jamalul Kiram III who set camp in Tanduo village in February 12.

The sultan earlier declared a “unilateral ceasefire” in response to Wednesday’s call by UN Secretary General Ban Ki-moon to end the violence and find a peaceful solution for the area in Sabah state, Abraham Idjirani, a spokesman for Kiram, said in Manila.

“Our troops will be on defensive stance,” Mr. Idjirani said. “We will wait for the UN to come up with a comprehensive mechanism on the withdrawal of the troops of the sultanate of Sulu.” But the proposed withdrawal did not mean that they would abandon their claim to the area, he said.

The sultanate leased the land in 1878 to the British North Borneo Co, which passed it to Malaysia after it gained independence. Kuala Lumpur currently pays the sultan 5,300 ringgit per year in token rent.

A total of 52 Filipino gunmen have been killed during a week of skirmishes between Malaysian forces and followers of a Philippine sultan who assert their claim over the eastern state of Sabah, Malaysia’s police chief said on Thursday.

“As of now the death toll among the Sulu intruders stands at 52,” said police Inspector—General Ismail Omar. “At this point in time no further information can be given.” Eight Malaysian police officers have also been killed since fighting broke out Friday in Lahad Datu, 1,600 kilometres east of Kuala Lumpur, where the Filipino gunmen have set up camp since February 12.

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