The Gaza Strip's Hamas-led government on Thursday executed two Palestinians convicted of aiding Israel in the assassination of Palestinian militants, a move that highlighted the deep divisions that endure between the two main Palestinian political factions.

The executions -- carried out without the approval of Palestinian Authority President Mahmoud Abbas, who is based in the West Bank and is part of the rival Fatah movement -- represented a direct rebuke of Abbas's authority amid stalled efforts at reconciliation. While Hamas controls Gaza, Abbas and Palestinian Prime Minister Salam Fayyad govern the West Bank from Ramallah.

The killings also came amid persistent tension in Gaza, where the Israeli army is continuing military operations to try to stop rocket fire into Israeli communities. They marked the first time the Hamas government has executed "collaborators" since the movement took control of Gaza in 2007.

The two men were convicted in a military court of providing intelligence to Israel that led to the assassinations of wanted Palestinian militants Amr Abu Setta, Bakr Hamdan and Husam Hamdan between 2002 and 2006, according to the Hamas-run Interior Ministry. Naser Abu Freih, a 34-year-old former Palestinian police officer from the Jabalya area, also was convicted of collaborating with Israel since 1998, the ministry said.

Freih and Muhamad Ibrahim Ismail, 36, of Rafah were killed by a firing squad early Thursday. Their relatives, who saw them Wednesday night, were summoned to pick up their bodies.

According to the nongovernmental Palestinian Center for Human Rights, based in Gaza, 10 other Palestinians face death sentences after being convicted of collaboration.

Amnesty International condemned Thursday's killings, calling them an "extremely retrograde step by Hamas."

Ghassan Khatib, a spokesman for the Palestinian Authority, called the executions illegal, because under Palestinian law the president is required to approve the killing of collaborators. Hamas does not recognize Abbas's standing as president, however, because his term has expired.

After winning a 2006 election and participating briefly in a unity government with Fatah, Hamas seized control of the Gaza Strip in 2007 and chased out leaders from the Palestinian Authority. The split has left the Palestinians politically and geographically bifurcated, complicating U.S. efforts to resume Israeli-Palestinian peace talks.