KUALA LUMPUR, Malaysia (AP) — Malaysian security forces have surrounded armed intruders on Borneo who are believed to be from the southern Philippines, police said Thursday.

The intruders have been ordered to surrender their weapons, national police chief Ismail Omar said, adding that “the situation is under control and the public need not worry.”

Ismail’s statement late Wednesday did not disclose the number of suspects or how they were armed. Malaysia’s national news agency, Bernama, cited unidentified police sources as saying that the intruders comprised more than 100 foreigners wearing military fatigues.

Malaysia’s Sabah state is less than an hour by speedboat from the southern Philippines, which has long been wracked by a Muslim separatist insurgency.

Ismail said the group landed in Sabah’s largely rural, coastal district of Lahad Datu on Tuesday following “troubles in the southern Philippines.”

Other police representatives in Kuala Lumpur and Sabah on Thursday confirmed the intrusion but said they could not elaborate beyond Ismail’s statement.

Security on Malaysia’s sea border with the Philippines has been problematic for Sabah, where tens of thousands of Filipino have tried to immigrate over the past few decades.

In 2000, southern Philippine gunmen slipped twice into Sabah and abducted people for ransom, including tourists from a diving resort.

One of the most recent kidnappings involved two Malaysians snatched from a plantation in Lahad Datu in November. They were believed to have been taken to the southern Philippines.