JEDDAH, Saudi Arabia — Saudi Foreign Minister Saud al-Faisal accused Syria's President Bashar al-Assad of "manoeuvring" to gain time, at a joint news conference Sunday with UN chief Ban Ki-moon.

"Every initiative has been accepted by the Syrian regime and was not implemented. This is a way used by the regime to gain time," Prince Saud told reporters in the Red Sea city of Jeddah.

"He is playing for time and manoeuvring," he said, referring to Assad.

The Saudi minister's remarks came immediately after Assad said Sunday that his government is faced with a foreign plot to destroy Syria.

Arab leaders on Saturday called on the United Nations to act to stop bloodshed that has persisted for nearly 15 months despite a UN-backed peace plan that includes the deployment of nearly 300 observers.

The plan was drawn up by UN-Arab League envoy Kofi Annan, who on Saturday singled out Assad and his regime as the key to resolving the conflict as he warned of the spectre of all-out sectarian warfare.

Annan "will present his report (on Syria) in a few weeks... It must be clear, straightforward, precise and transparent," Prince Saud said. "We hope the United Nations takes a firm stance."

Ban, who described the situation in Syria as "troubling", called onto the government in Damascus to "abide to the Annan plan," adding that "all violence must stop in all its forms."

Since the so-called ceasefire began on April 12, as many as 2,300 people have been killed out of the more than 13,400 who have died in Syria since the uprising against Assad's regime began in March 2011.

The Saudi foreign minister, who has repeatedly voiced his country's support for arming Syria' rebels said: "We support creating a buffer zone in Syria which the oppressed can take refuge in... but this is the responsibility of the UN Security Council as the Arab League can't do this."

Because of the worsening violence and Assad's failure to meet commitments under the agreed peace plan, the United States has warned that it may not agree to renew the UN observer mission when its mandate expires on July 20.

Tensions from Syria have also spilled across into neighbouring Lebanon, where clashes between pro- and anti-Damascus gunmen left 14 dead and 48 wounded over the weekend in the northern city of Tripoli.

"What's going on in Tripoli is by no doubt an extension of the events in Syria. We have noticed since a while ago that the regime is turning the conflict into a sectarian conflict," said Prince Saud.

"These things do not only threaten Lebanon but they also threaten Syria itself as it might divide the country and this is a very dangerous phenomenon," he said.

"If this conflict spreads, it will create circumstances which are worse than the crisis itself."