Israeli soldiers raided the offices of three Palestinian nongovernmental organizations in downtown Ramallah early Tuesday, rifling files and seizing laptop computers in a rare sweep in the heart of the de facto capital of the Palestinian Authority, the groups said.

The Israeli army said it had searched “several offices” affiliated with the Popular Front for the Liberation of Palestine (PFLP), a militant leftist faction, but gave no further details.

Early Tuesday, soldiers broke into the offices of the Palestinian NGO Network; the Union of Palestinian Women’s Committees; and Addameer, a group offering legal aid to Palestinian prisoners, officials of the groups said.

Sahar Francis, executive director of Addameer, said that four laptops, a hard disk and a video camera were taken and that files may have been copied from the group’s computer server, which appeared to have been tampered with. Filing cabinets were ransacked, she said, and papers were strewn on the floor.

Samah Darwish, executive director of the Palestinian NGO Network, which coordinates among nongovernmental organizations, said internal doors had been broken down and files were scattered in several rooms. She said one was an office serving the international campaign for boycott, divestment and sanctions against Israel, known as BDS, which advocates for boycotting Israeli products abroad, urges foreign companies not to do business with Israel and calls for economic sanctions against Israel because of its policies toward the Palestinians. “Boycott Israel” leaflets littered the floor, the Reuters news service reported.

Darwish said she believed the raid was linked to her group’s activities, such as support for human rights monitors and prisoners’ rights advocates, as well as to the recent successful Palestinian bid at the United Nations for recognition as a nonmember observer state.

“This is a double message,” Darwish said in a telephone interview. “We have been raising many questions regarding Israeli violations, and it is also related to what happened at the U.N. They are sending a message that, ‘We are here, and you still cannot do anything to stop these violations.’ ”

Francis said Israeli security forces also have stepped up arrests in West Bank villages since the U.N. vote, which, along with Tuesday’s raid, “could be a message that you are not protected, even with your status at the U.N.”

An Israeli military spokeswoman declined to comment on the timing of the raid or what was seized, saying that details of the operation remain classified.

The Union of Palestinian Women’s Committees, which works to improve conditions for Palestinian women, is known to be affiliated with the PFLP, which is considered a terrorist group by Israel and the United States.

The faction has asserted responsibility for several suicide bombings and rocket attacks on Israel from the Gaza Strip. In 2001, it assassinated an Israeli cabinet minister, Rehavam Zeevi, in retaliation for the killing of its leader in an Israeli helicopter strike in Ramallah.

The other two organizations whose offices were raided deny any political affiliations, although Addameer has represented prisoners affiliated with the PFLP, as well as from other factions.