UN Secretary-General Ban Ki-moon on Friday started a series of consultations with the United Nations member states on Syria amid escalating tension about the war-torn country.

Ban, who returned to New York on Thursday night from his shortened European tour, first gave the permanent members of the UN Security Council an overview of work by UN inspectors who arrived in Syria on Aug. 18 to investigate the alleged use of chemical weapons there, UN spokesman Martin Nesirky told reporter here, adding that Ban will reach out to other member states.

The team, led by Swedish scientist Ake Sellstrom, visited the affected sites, including the location of an alleged Aug. 21 attack in the Ghouta area outside Damascus, the Syrian capital, interviewed victims and doctors, and collected samples, he said.

"The team ... is now packing up and they will be leaving Damascus tomorrow," he said, adding that the inspectors will return to The Hague, the Netherlands, where the headquarters of the Organization of the Prohibition of Chemical Weapons (OPCW) is based.

The UN fact-finding team was set up in March at the request of the Syrian government to establish whether chemical weapons were used, rather than who used the lethal weapons.

The Syrian government and the opposition have been accusing each other of using chemical weapons in the fighting.

Also on Friday, the United States pressed its case for a limited military strike against Syria, though U.S. President Barack Obama said in the same day that he has not made a final decision in this regard.

Before his return to New York, Ban had engaged in discussions with world leaders on the current situation in Syria.

On Thursday, Ban said he spoke over the phone with the U.S. President Barack Obama about how the United Nations and the United States could work together to "expedite the process of the investigation."

The secretary-general said he expressed his hope that the investigation team should be allowed to continue their work as mandated by the member states to probe the alleged use of chemical weapons.

Ban and other senior UN officials have repeatedly urged to seek diplomatic options to bring all the concerned parties in Syria to the negotiation table, and stressed there is no military solution to the crisis.

As for speculation that the West is set to take military action, the secretary-general said he would not speculate on anything of which he is not aware.

"If there needs to be any such unilateral or military action ... As secretary-general, I would like to emphasize that it is the Charter that provides the framework for action to ensure international peace and security," he added.