Work of the UN expert team fresh from investigating the alleged use of chemical weapons in Syria was "progressing well," chief UN spokesman said Sunday, on the eve of its first samples being sent on an accelerated timeline to laboratories for evaluation.

Martin Nesirky, UN Secretary-General Ban Ki-moon's spokesman, told reporters at an unusual Sunday morning briefing here at UN headquarters that the head of the mission, Ake Sellstrom of Sweden, told Ban in a telephone call Sunday that "two Syrian officials were observing the process," as part of the agreement to allow the investigators into Syria.

Ban has briefed the five veto-wielding permanent members of the Security Council on the team's progress and intended to speak soon with the 10 elected members of the council, said the spokesman, who did not give any further details of planned meetings or conversations.

"Sellstrom, who has just returned (Saturday) to The Hague with the rest of his expert team, after working in Syria from Aug. 19- 31, briefed the secretary-general on the next stages of the investigation process," Nesirky said, adding that samples will begin to be transferred to laboratories on Monday.

The whole process will be done strictly adhering to the highest established standards of verification recognized by the Organization for the Prohibition of Chemical Weapons (OPCW), he said.

"In light of the horrendous magnitude of the Aug. 21 incident in the Ghouta area of Damascus, the secretary-general asked Dr. Sellstrom to expedite the mission's analysis of the samples and information it had obtained without jeopardizing the scientific timelines required for accurate analysis, and to report the results to him as soon as possible," said the spokesman, noting they "also discussed ways to further accelerate the process."

However, Nesirky explained that no timeline has been specified. The UN chief is "very keen as is the rest of the international community that this should be done as quickly as possible, but you need to be able to adhere to the standards so that the scientific process of verification is credible."

With regard to U.S. claims of having hard evidence of chemical weapons use in Syria, the spokesman said all member states of the United Nations were welcome to contribute verified credible information for possible consideration.

The UN mission "is uniquely capable of establishing in an impartial and credible manner" whether chemical weapons were used in Syria, said the spokesman.

Ban has thanked Sellstrom for his work and for the performance of the team while in Syria in spite of "the difficult and dangerous circumstances."

The first time the team headed out of Damascus in a convoy of white vehicles marked "UN", the lead sport utility vehicle was hit by sniper fire. However, while the damage to the car was extensive enough to take it out of service, no one was injured.

Nesirky said Saturday that Ban was briefed by his disarmament chief Angela Kane, who left Syria Friday. The spokesman told reporters the team's immediate job was to sort out the information collected, interpreting interviews and collating evidence in preparation for evaluation.

He said earlier that the alleged evidence samples brought back were being sent to different unidentified laboratories to assure security and accuracy of assessments while remaining within the bounds of chain-of-custody strictures.

The team originally was granted permission to investigate allegations of chemical weapons use, outlawed under international law, at Khan al-Assal and two other sites, not named for security reasons. But, following reports that chemical weapons used in Ghouta on Aug. 21 had killed hundreds including women and children, Ban asked Sellstrom to prioritize investigating the Ghouta allegation.

Plans to visit the original three sites were put on hold and the team went to Ghouta. Nesirky said Sunday a UN team would return to Syria at an unspecified time in order to carry out the rest of its assignment. Composition of the second team was not released. Endite