BEIRUT -- Under growing pressure, Syria agreed yesterday to allow a UN investigator to question members of President Bashar Assad's inner circle about the assassination of Lebanon's former prime minister, an inquiry some believe might shake his regime.
The visit by investigator Detlev Mehlis highlights the vulnerability of Assad's government, which has become increasingly isolated, facing pressure over Lebanon and Iraq.
Mehlis visited Damascus for the first time since his team began its inquiry into the Feb. 14 killing of Lebanon's former prime minister, Rafik Hariri, in a bombing. The United Nations said yesterday it is giving Mehlis until Oct. 25 to complete his investigation -- an extension of 40 days.
Damascus invited Mehlis after he accused Syria of delaying his investigation by ignoring requests to question Syrian officials. During the German prosecutor's brief visit yesterday, he negotiated a deal on holding interviews.
''An agreement was reached on measures and arrangements for meeting with Syrian witnesses," said a statement carried by Syria's state-run SANA news agency after Mehlis met with Foreign Ministry official Riyadh Dawoody.
Mehlis returned to Beirut and is expected to visit Syria again next week, SANA said.
His push to question Assad's allies increases pressure on Syria after the UN investigation accused four once-powerful Lebanese generals who carried out Syrian policy in Lebanon of involvement in Hariri's assassination.
''This, without doubt, is the biggest challenge that has faced the president," said Yassin Haj Saleh, a Syrian writer.
''I would not be surprised if the regime felt its fate is uncertain, especially if the investigator confronts it with evidence of Syrian involvement," added Haj Saleh, who was jailed for 16 years for belonging to a communist party.
Syria has denied involvement in the murder. On Sunday, it promised to cooperate with the inquiry, which began June 17.
Mehlis has said there are no Syrian suspects, and those he wants to question will stand as witnesses.
Lebanese media have said those include Syria's last intelligence chief in Lebanon, Brigadier General Rustum Ghazale; two aides; and Syria's interior minister, Ghazi Kenaan, who was intelligence chief in Lebanon until five years ago.