UNITED NATIONS - The US, together with its allies, and Russia on Friday tabled rival draft resolution on the authorization of an advance team of unarmed military observers for Syria in order to monitor a ceasefire between the Syrian government forces and armed opposition fighters.

The US, Colombia, France, Germany, Morocco, Portugal and the United Kingdom jointly submitted a draft resolution while Russia put forward a rival one, likely putting off the council vote, which is expected late Friday, until Saturday.

The 15-nation Security Council began its meeting behind closed doors on Syria at around 3 pm EST (2000 GMT) on Friday, and the meeting is still going on, UN officials said.

The two sides agreed to the council's approval of the advance team of up to 30 unarmed military observers for Syria, where a ceasefire is reportedly honored by both the government forces and armed oppositions, according to the two drafts obtained by Xinhua.

They also both supported the good offices of Kofi Annan, the UN and Arab League special envoy for Syria, and its six-point plan to end the year-long crisis in Syria, which has been plunged into violence since March 2011.

The two drafts also reaffirmed the council's "strong commitment to the sovereignty, independence, unity and territorial integrity of Syria, and to the purposes and principles of the (UN) Charter."

However, the rival drafts argued over whether Syria should give immediate guarantees of freedom of access to the mission and whether the council should warn Syrian President Bashar al-Assad of further measures if he does not keep commitments.

The US draft "demands" the Syrian government "implement visibly its commitment in their entirety," while the Russian version "calls upon" Damascus to do the same thing.

The Syrian government said it accepted Annan's peace plan and pledged to comply with the ceasefire deadline.

Russian UN Ambassador Vitaly Churkin, who spokes to reporters on Friday after the council's closed door discussions on Syria on Friday morning, criticized the US draft for asking too many work to be done, saying, "We have put together a shorter version of (the US) text. ?

"We had this understanding yesterday that it should be to the point, pragmatic, specific about putting in boots on the ground, (an) advance party of the monitoring team," Churkin said.

The two drafts were presented to the council in response to a request by Annan to send the UN observers to monitor compliance with the truce. If the ceasefire holds, a larger mission with up to 250 members could follow.

Annan's spokesman Ahmad Fawzi told reporters in Geneva on Friday that a dozen of UN observers is ready to enter Syria, where the ceasefire has been "relatively respected."

The advance team is "standing by to board planes and to get themselves on the ground as soon as possible," once the Security Council gives approval for the mission as hoped, Fawzi said. "We hope both sides (in Syria) will sustain this calm, this relative calm."

Meanwhile, Fawzi said that the truce is just a first step on a long way to peace.

"This is only the beginning of a long road towards reconciling and towards building the future that Syrians aspire to, where there are no detentions without cause, where law enforcement guarantees peace and security in the street - not the military," he said.

Anna said in a statement issued in Geneva on Thursday that he is "encouraged" by reports that the cessation of hostilities in Syria "appears to be holding," urging all Syrians to seize opportunity to implement the agreed six-point peace plan.

Annan had previously stated that, once the Syrian government would complete the withdrawal of troops by April 10, all parties should move immediately to cease all forms of violence, so that a complete cessation is in place by Thursday, April 12.