Kofi Annan's six-point peace plan for Syria remains "on track," his spokesman insisted Friday, despite skepticism from the U.S. and others about the cease-fire that has been largely ignored by President Bashar Assad's forces.

The assessment came a day after the Obama administration offered a bleaker view — saying it may be time for the world to acknowledge that the cease-fire is not holding in Syria and seek another approach.

"The Annan plan is on track and a crisis that has been going on for over a year is not going to be resolved in a day or a week," said Ahmad Fawzi, the international envoy's spokesman. "it's going to take a little more time to pull all the strings together. But rest assured that they are being pulled together."

Most observers agree the plan by Annan has done little to stem the bloodshed, but so far nations backing it have been unwilling to say it is dead. U.S. officials say the plan is failing mainly because of Syrian government violations.

Fawzi told a U.N. briefing in Geneva that negotiators are meeting with Assad's government and the opposition separately, trying to lay the groundwork for the two sides to negotiate directly with each other.

The U.N. now has around 50 truce observers in Syria, and has commitments for about 150 of the 300 observers that it expects to have on the ground by the end of May, Fawzi said.

Assad's government and the opposition are blaming each other for flouting the cease-fire. Annan, the joint U.N.-Arab League envoy, is scheduled to brief the U.N. Security Council on Tuesday from Geneva with the latest assessment.

The observers have been touring restive parts of the country where the U.N. estimates 9,000 people have been killed since an uprising against Assad's regime began in March 2011. They have been documenting violations by both sides of the April 12 cease-fire, including Syrian heavy weapons deployed in populated areas.

"There are no big signs of compliance on the ground. There are small signs of compliance. Some heavy weapons have been withdrawn. Some heavy weapons remain. Some violence has receded, some violence continues. And that is not satisfactory," Fawzi said.

There are also several dozen civilian staff members already in Syria to support the observers.

Syrian opposition groups were planning nationwide protests Friday, the day after security forces raided dormitories at the usually safe haven of Aleppo University and killed four students.

On Thursday, the White House press secretary, Jay Carney, told reporters that "if the regime's intransigence continues, the international community is going to have to admit defeat."

The head of the U.N. observers, Norwegian Maj. Gen. Robert Mood, told reporters Thursday in Syria there is still "a good chance and an opportunity" to break the cycle of violence. Asked whether the observers are being targeted, Fawzi said "categorically, no" despite suicide blasts occurring near a hotel where some were staying.