At least 24 people were killed in Syria on Saturday. Troops shelled areas in Damascus and its suburbs in the seventh day of fierce fighting with rebels, who claimed responsibility for the Wednesday bomb attack that killed the defense minister and three aides to Assad, including his brother-in-law. And fighting threatened to spill over the Jordanian border.

"The Syrian government has manifestly failed to protect civilians, and the international community has a collective responsibility to live up to the UN charter and act on its principles," Ban said on Saturday.

Ban said he would send an envoy mission to Syria to assess the situation, including French diplomat Herve Ladsous.

"The situation is fluid and unpredictable, but the path to peace is clear. There must be an end to killing and human rights violations, and a rapid move towards a peaceful, Syrian-led political transition and political dialogue," Ban said.

Heavy clashes were reported in Syria's second city Aleppo on Saturday, regime forces reportedly shelling several neighbourhoods. Hundreds were believed to be fleeing their homes. Until recently, the city has largely remained loyal to Assad.

Frontier fighting

Violence between the rebels and government forces threatened to spill over the border with Jordan. Jordanian security sources said Saturday that border clashes escalated into all-out war on Saturday, with heavy shelling and rocket fire just a few meters from Jordanian soil.

The rebel Free Syrian Army briefly gained control of the border Naseib crossing before being repelled again by Syrian troops. Such fighting is expected to continue as the rebels seek to secure safe passage of Syrian civilians and deserters from Syria by controlling the border areas.

"It has always been the Free Syrian Army's priority and responsibility to ensure that the people are able to find places of safety and receive medical treatment," said Abu Ahmed, a member of the Syrian opposition grouping, the Local Coordination Committees.

The governor of the Iraqi province of Ninevah said on Saturday that the rebels had taken control of a crossing close to the town of Rabiya, the second crossing that rebels have seized after taking control of a border post near to Qaim on Thursday.

Although refugees tried to cross the border, Iraqi officials said they would not be allowed to enter the country.

Security Council's vote

Meanwhile, Ban praised the Security Council's decision on Friday to allow for a "final" 30-day mandate extension to the UN Supervision Mission.

Both Russia and China voted in favor of extending the mission after having blocked a text that would have imposed sanctions.

"The unanimous vote on resolution 2059 is a constructive sign," Ban said.

In addition to seeking support from the international community, Ban also called on the warring parties in Syria to end the violence without any conditions.

tm/rc (AFP, dpa)