Malaysian police said on Friday they have arrested more than 50 people in a remote state since the start of a nearly month-long incursion by Filipino Islamists.

Malaysia has said previously that clashes between the gunmen and its security forces had left 60 people dead and has rejected a call by the fighters’ leader for a ceasefire in a farming region where the militants were being pursued.

In announcing the arrests, federal police chief Ismail Omar said they had all occurred in other areas of the state of Sabah, outside the battle zone where the militants and armed forces were facing off.

“Outside the operation area, police already arrested certain suspects who we believe have links to the invaders,” Ismail said.

He said more than 50 had been arrested, including men and women. He declined to give any further details on the identities of those arrested, including whether they were foreigners or Malaysians.

Scores of followers of a self-proclaimed Philippine sultan landed in the state on Borneo island last month to assert a long-dormant territorial claim in what has become Malaysia’s worst security crisis in years.