KUALA LUMPUR, Malaysia » Malaysian security forces gunned down 31 Filipino intruders in Borneo on Thursday, (Wednesday in Hawaii) the highest number of casualties in a single day since nearly 200 members of a Philippine Muslim clan took over an entire village last month, police said.

However, representatives of the Filipino group denied their members had been killed.

The armed clansmen have wreaked political havoc for both Malaysia and the neighboring Philippines by trying to stake a long-dormant royal territorial claim to Malaysia’s sprawling, resource-rich state of Sabah in Borneo.

Most of the Filipinos had eluded capture in a coastal Sabah district filled with palm oil plantations and forested hills after Malaysian forces attacked them with airstrikes and mortar fire on Tuesday.

Police and military forces tracking them waged a fierce gunbattle that ended in the deaths of 31 clansmen Thursday, national police chief Ismail Omar said, adding that no Malaysians were injured.

But Abraham Idjirani, a Philippine-based representative for the clansmen, said he spoke by telephone Thursday evening with the group’s leader, who insisted all of them remained accounted for. He claimed Malaysian forces had instead killed dozens of civilian villagers.

The conflicting claims could not immediately be explained.

Ismail said at least 52 Filipinos have now been killed in the past week since hostilities in the Sabah security crisis escalated. Eight policemen also were fatally shot by the Filipino clansmen and their allies last week in various parts of Sabah.

Less than two hours before the announcement of the casualties, Prime Minister Najib Razak rejected a cease-fire call by Philippine-based members of the clan led by Jamalul Kiram III, who claims to be the sultan, or hereditary ruler, of the southern, predominantly Muslim province of Sulu in the Philippines.

A brother of Kiram, the sultan who lives in Manila, is heading the group in Sabah. Kiram had ordered them to observe a unilateral cease-fire starting Thursday afternoon by holding their current position and taking a defensive posture.

Najib responded by saying Malaysia would accept only unconditional surrender by the clansmen, who slipped into Sabah by sea around Feb. 9.

“They have to surrender their arms. They have to do it as soon as possible,” Najib said at a nationally televised news conference.

“Don’t believe this offer of a cease-fire by Jamalul Kiram,” Malaysian Defense Minister Ahmad Zahid Hamidi wrote on Twitter. “For the sake of the people of Sabah and Malaysia, eliminate all militants first.”

Idjirani said a cease-fire would be in line with a statement of concern by U.N. Secretary-General Ban Ki-moon late Wednesday.

Ban “urges an end to the violence and encourages dialogue among all the parties for a peaceful resolution of the situation,” according to the statement issued by Ban’s representative.

Ban voiced concerns about how the crisis might affect civilians, including Filipino migrants in Sabah, and urged “all parties to facilitate delivery of humanitarian assistance and act in full respect of international human rights norms and standards,” according to the statement.

Malaysia’s government has insisted it made every effort to coax the Filipinos to leave and had to use force after the group fatally shot two policemen last week. Six other police officers were ambushed and killed by other Filipinos believed to be linked to the clansmen in another Sabah district.

The Filipinos say Sabah belonged to their royal sultanate for more than a century and should be handed back. Malaysia has dismissed their claim to the state, which has been part of Malaysia for five decades.

An estimated 800,000 Filipinos, mostly Muslims from insurgency-plagued southern provinces, have settled in Sabah over the years to seek work and stability.

Associated Press writers Hrvoje Hranjski and Oliver Teves in Manila, Philippines, contributed to this report.