The 2013 Lahad Datu incursion was a military conflict in Lahad Datu District, Sabah, Malaysia, that started on 11 February 2013, lasted until 24 March 2013. The conflict began when 235 militants, some of whom were armed, arrived by boats to Lahad Datu from Simunul island, Tawi-Tawi, in the southern Philippines. The group, calling themselves the "Royal Security Forces of the Sultanate of Sulu and North Borneo", were sent by Jamalul Kiram III, one of the claimants to the throne of the Sultanate of Sulu.
Kiram III stated that their objective was to assert an unresolved territorial claim of the Philippines to eastern Sabah. Malaysian security forces surrounded the village of Tanduo in Lahad Datu, where the group had gathered. After several weeks of negotiations and deadlines for the intruders to withdraw, and prompted by the killing of Malaysian police force members, the security forces launched a major operation to flush out the militants. At the end of the standoff, around fifty-six militants were killed, together with six civilians and ten Malaysian security force personnel. The rest of the militants were either captured or escaped back to the Philippines.