BEIRUT, Lebanon - The chief UN investigator into the assassination of a former Lebanese premier, armed with new powers from the Security Council, has summoned six senior Syrian intelligence officers, including President Bashar Assad’s brother-in-law, for questioning, a Lebanese official said on Saturday.

The official, close to the UN team investigating Hariri’s killing, said chief UN investigator Detlev Mehlis sent the summons to the Syrian government via the United Nations on Wednesday.

“Mr. Mehlis has sent a letter to UN Secretary-General Kofi Annan demanding to question at least six Syrian officials,” the official told The Associated Press. He spoke on condition of anonymity because he was not authorized to speak to the media on this sensitive issue.

There was no immediate Syrian comment due to the Eid Al Fitr holiday.

The London-based pan-Arab newspaper Al Hayat reported on Saturday that Mehlis wanted to question six senior Syrian officers at the UN commission’s headquarters at the hilltop Monteverde Hotel east of Beirut, and not in Syria.

This week’s Security Council Resolution 1636 gave Mehlis the power to question any Syrian at the location and under conditions of his choosing.

Despite its declared readiness to cooperate with the UN probe into Hariri’s killing, the Syrian government, citing the country’s sovereignty, is reportedly against allowing Syrian witnesses or suspects to be questioned by UN investigators outside Syria. It is particularly sensitive for Syrians to be questioned in Lebanon because of security concerns for their own safety.

Al Hayat said the men Mehlis wanted to question included Assad’s brother-in-law, Gen. Assef Shawkat, chief of Syria’s military intelligence service; Maj. Gen. Bahjat Suleiman, former chief of Syria’s internal intelligence apparatus; and Brig. Gen. Rustum Ghazale, the last Syrian intelligence chief in Lebanon who was in charge when Hariri was assassinated.

The other three senior officers listed in the summons did not include Assad’s brother, Maher, whose name was mentioned, along with Shawkat, in Mehlis’ report to the Security Council last month.

Lebanese prosecutor-general Saeed Mirza declined to comment on Al Hayat’s report when contacted by The Associated Press. “I don’t know. You have to ask Mr. Mehlis,” Mirza told The AP on Saturday. (AP)