JERUSALEM — The director of a major Palestinian Arab security force who coordinated security directly with American officials is suspected of being an agent for the Hamas terror organization, The New York Sun has learned.

Yussef Issa, director of the Preventative Security Services, is accused by President Abbas’ Fatah organization of working on behalf of Hamas, Fatah sources said. The PSS was the largest of the American-backed Fatah security forces that operated in Gaza until Hamas took over the territory last month. The force continues to operate in the West Bank and coordinated security there with America.

Mr. Issa was one of a handful of top Palestinian militia leaders to hold regular security meetings with Lieutenant General Keith Dayton, the American security coordinator in the region, and with General Dayton’s American team. The meetings were largely aimed at implementing the Dayton Plan, which called for America to strengthen Mr. Abbas’ security forces against the rival Hamas group.

Last week an official Fatah committee presented Mr. Abbas with a 200-page investigation into the conduct of Fatah leaders and security officers who lost the Gaza Strip to Hamas. The report found the Fatah security forces in Gaza were infiltrated by “hostile elements,” including Hamas.

A member of the inquiry committee said last week some 60 Fatah security officers would face courts-martial shortly. But Fatah sources said the actual number of suspected Hamas infiltrators was much larger.

A senior Mr. Abbas aide, Nabil Amr, who served on the committee, told reporters Fatah security forces were in a “state of infiltration” by Hamas.

Asked whether Mr. Issa was listed as a suspected Hamas agent, a member of Mr. Amr’s team told the Sun he could not release any names. But the team member pointed out Mr. Issa has been living in Egypt since Hamas took over the Gaza Strip last month, refusing to return to the Fatah-controlled West Bank, and that Mr. Abbas recently downgraded Mr. Issa from colonel to the rank of soldier.

“So there’s your answer. You can infer from that what you will,” said the Mr. Amr team member.

A top Preventative Security Services source in Ramallah said Issa is suspected of being “one of the most important Hamas infiltrators in Fatah.”

The source said Mr. Issa and Siad Siam, who served as Hamas’ Interior Minister and is a founder of Hamas’ so-called Special Force militia in Gaza, both married sisters from the same family. The source speculated the family relations may have helped facilitate Mr. Issa’s working on behalf of Hamas but he said Mr. Issa is suspected of accepting significant sums of money from the terror group.

“Hamas has been buying off agents at all levels both in Gaza and in the West Bank,” said the Preventative source. “The buying is still going on.”

Hamas last month overtook all American-backed Fatah security compounds in the Gaza Strip and reportedly seized large quantities of American weaponry. According to Preventative sources, one hour before Hamas siezed the main Preventative Security Service building in Gaza City, Mr. Issa was smuggled out of the compound by Hamas’ Special Forces.

The information comes as America in recent days pledged large sums of aid to help bolster Mr. Abbas’ militias and security forces in the West Bank. American security coordinators continue working to arm and train Fatah militias, including the Preventative Security Services and Abbas’ Force 17 Presidential Guard units. Thousands of assault rifles last week reportedly reached Fatah security compounds in the West Bank cities of Jericho and Ramallah.

Abu Abdullah, a senior member of Hamas’ “military wing,” told the Sun Fatah in the West Bank is heavily infiltrated by Hamas.

“Fatah hasn’t yet touched the extent of our infiltration [of their groups] in the West Bank.”

Muhammad Abdel-El, spokesman for the Hamas-allied Popular Resistance Committees terror group, told the Sun his group and Hamas have infiltrated “very deep” in Fatah.

“We already are planning to obtain American weapons and takeover the West Bank like we did in Gaza with help from the Palestinian resistance, including elements in Fatah, the Al Aqsa Martyrs Brigades and the Fatah Security Services. The Committees and Hamas has infiltrated very deep in Fatah,” Abdel-El said.

Top Hamas leaders vowed to soon stage a coup in the West Bank.

“The moment of our taking control in the West Bank is not far away,” said Abu Yousuf, a senior aide to Hamas leader in Gaza Ismail Hineyah.

Abu Oubaida Al Jara, chief of Hamas’ so-called special forces in Gaza, called on all Fatah members “not to resist because the Islamic project (Hamas) is coming very soon to the West Bank.”