A Syrian official said on Wednesday, however, that Damascus has proposed that the UN commission chief Detlev Mehlis interview Syrians at UN offices on the Golan Heights.
The Golan Heights have been occupied by Israel since 1967.
Mehlis, a German prosecutor, reportedly wants to interview six top Syrian security officials at its offices in Monteverde, east of Beirut, over the former Lebanese prime minister's killing in a February bomb blast.
They include a brother-in-law of President Bashar al-Assad, Assef Shawkat, who heads Syrian military intelligence.
"(Mehlis) has submitted a request to Syria and is still awaiting a response," UN under-secretary-general Ibrahim Gambari said at a joint press conference in Beirut with Prime Minister Fuad Siniora on Wednesday.
"It's important for Syria to be in direct contact with Mehlis over the means to carry on with the investigation ... They say Mehlis is giving the impression of being stubborn, which is not true," he said.
"He has said what he wanted and is waiting for a response," said Gambari.
UN prosecutor Mehlis wants to
hold the interviews in Lebanon
"Syria must accept the request. Let's give Syria and Mehlis the time needed to find a solution," said the UN official. "I think he has not received an official response (from Syria) yet."
Last week, Damascus said it has slapped travel bans on Syrian nationals named in an interim report released last month on the probe of the UN commission whose mandate runs out in mid-December.
Apart from Shawkat, according to Beirut dailies, the others whom Mehlis wants to question include Bahjat Suleiman, former domestic intelligence chief, the former head of military intelligence in Lebanon, Rustom Ghazaleh, and his deputy Jameh Jameh.
"Syria has no other choice but to cooperate with the enquiry," said Gambari, adding that the UN Security Council resolution calling for Damascus to fully aid the probe had been supported "by friends of Syria", apparently referring to Russia, China and Algeria.
Syria has proposed that Mehlis interview Syrians at UN offices on the Golan Heights, a Syrian official said on Wednesday.
The official, who asked not to be named, said Damascus would send a Foreign Ministry legal adviser to meet the head of the UN investigation team, Detlev Mehlis, "soon".
The Mehlis report named close
relatives of President al-Assad
"In a letter by Justice Minister Mohammad al-Ghafari to Mehlis on November 9, Syria proposed the offices of the United Nations in the occupied Golan Heights or any other place in Syria that he chooses," the official said.
"Mehlis has been made aware of Syria's reservations about Beirut as a venue and the Foreign Ministry's legal adviser Mr Riad al-Daoudi will be sent to meet with him soon for consultations," the official said.
"Syria is willing to cooperate and this was said in letters by President Bashar al-Assad to world leaders and United Nations Secretary-General Kofi Annan," the official said. "The president explained Syria's position in full."
Anti-Syrian sentiment is still running high in Lebanon where many people say Damascus and its Lebanese allies were behind the attack.
Syria retains the support of some political groups in Lebanon, especially the Shia Amal and Hizb Allah factions.
Meanwhile, on a visit to Damascus, Russia's Security Council chief Igor Ivanov has expressed his country's satisfaction at Syria's cooperation with the probe.
"We are satisfied that Syria is contributing actively in applying the international resolution dealing with the enquiry into the assassination of Rafiq Hariri," Ivanov said afer talks with al-Assad on Wednesday.
Turkish Foreign Minister Abdullah Gul was also due in Damascus on Wednesday to urge al-Assad to enhance cooperation "in light with the fact that time is quickly running out", said a statement from Ankara.
Syria has denied accusations of a
hand in al-Hariri's assassination
Last week, al-Assad rejected international accusations of Syrian complicity in al-Hariri's murder but said that Damascus, despite its distrust of the process, would fully cooperate with the UN probe.
Al-Assad, however, said Mehlis had turned down a Syrian invitation to travel to Damascus to sign a legal protocol on the investigation, as well as proposals for the UN probe to move its work to Syria or the Cairo-based Arab League.
On Sunday US Secretary of State Condoleezza Rice stepped up her criticism of Syria, saying Damascus's attitude was "just not going to cut it".
"What I have seen so far (from Syria) is a lot of criticism of the process, criticism of the investigation," said Rice. "That's just not going to cut it."
However, al-Assad has said that his country is the target of a witch-hunt.
"Whatever we do or say to cooperate, the response is just going to be in a month that Syria is not cooperating. We have to be realistic, Syria is being targeted," he said.