Philippine President Benigno Aquino warned a sultan on Tuesday he would face the "full force of the law" if he did not end a standoff involving his armed followers in the Malaysian state of Sabah.
Aquino told Sultan Jamalul Kiram III to recall 180 of his followers, about 30 of whom were armed, from a fishing village on the island of Borneo where they have been facing off with Malaysian security forces for two weeks.
"If you choose not to cooperate, the full force of the laws of the state will be used to achieve justice for all who have been put in harm's way," Aquino said in a statement aired on national television.
"This is a situation that cannot persist. If you are truly the leader of your people, you should be one with us in ordering your followers to return home peacefully."
He warned Kiram that he had also ordered an investigation "into possible violations of laws by you, your followers, and collaborators engaged in this foolhardy act".
Aquino cited a constitutional provision renouncing war as an instrument of policy and a law prohibiting citizens against inciting war, which is punishable by up to 12 years in prison.
Kiram's followers made a boat trip from their homes on remote islands in the southern Philippines to occupy the Malaysian fishing village two weeks ago, after the sultan gave them a blessing to live there.
Kiram says he is the head of the Islamic Sultanate of Sulu, which once controlled parts of Borneo, including the site of the stand-off, as well as southern Philippine islands.
The sultanate leased northern Borneo to Europeans in the 1870s. While the sultanate's authority gradually faded as Western colonial powers exerted their influence over the region, it continued to receive lease payments for Sabah.
Heirs to the sultanate still receive nominal annual compensation from Malaysia.
One of the demands from the sultan is an increase in the amount of compensation paid. The sultan has also said his followers have a right to remain in Sabah because the land belongs to them, not Malaysia.
Aquino said his government was working with Malaysian authorities in an effort to peacefully resolve the standoff.