NEW YORK - UN-Arab League envoy Lakhdar Brahimi said Monday that the Syrian civil war is worsening, and that he sees no immediate prospect for its end.

"There is no prospect for today or tomorrow to move forward," Brahimi told reporters after briefing the UN Security Council on his recent talks with Syria's President Bashar al-Assad.

Brahimi said he had told Assad and others in Syria that there had to be "change" but acknowledged that for the moment there was a "stalemate" and he had no full peace plan to offer.

"There is no disagreement anywhere that the situation in Syria is extremely bad and getting worse, that it is a threat to the region and a threat to peace and security in the world," Brahimi said.

The envoy, who took over from Kofi Annan as international envoy on September 1, also appealed to the divided 15-nation Security Council for united backing for his efforts.

"If I do not represent the entire council then I am nothing," Brahimi said.

Brahimi told the 15-nation council that Assad's government estimates there are 5,000 foreign fighters in the conflict which it increasingly portrays as a "foreign conspiracy," a diplomat inside a closed meeting with the envoy told AFP.

He said Assad "knows that something must change," according to a second envoy in the meeting.

Assad, however, only wants to return to "the old Syria" which he and his father have ruled for more than 40 years, Brahimi was quoted as saying.

The former Algerian foreign minister painted a grim picture of the 18-month-old conflict in which the UN says about 20,000 people have died.

Brahimi told the council that the torture of detainees has become "routine" and that people were now afraid to go to hospitals which are in the hands of government forces.

The envoy estimated that 1.5 million people have now fled their homes and said Syria faces growing food shortages because harvests have been slashed by the fighting between government forces and opposition rebels.

He said more than 2,000 of Syria's 2,200 schools have been damaged and scores of teachers are among the dead.

The Syria war has divided the UN Security Council, with Russia and China resisting international action demanded by Western and many Arab nations.

Germany's Foreign Minister Guido Westerwelle said after meeting Brahimi in New York: "The situation in Syria is grave. We need to do everything we can to end the violence and the killing of so many innocent people."

The United States and its European allies have given strong public backing to the efforts of Brahimi.

"Germany supports the work of Mr. Brahimi in his very difficult job," Westerwelle told reporters. "Germany will continue to press for a united stance of the Security Council" on the conflict.

The Syria conflict is expected to dominate the annual UN General Assembly debate of world leaders which starts in New York on Tuesday.

US President Barack Obama, one of the first speakers, is expected to lead international attacks on the Assad government.

"His speech is likely to be sharply worded," said Richard Gowan of New York University's Center on International Cooperation.

"In what will probably be his last major international engagement before November's elections, he has a chance to scold Russia for its behavior over Syria," said Gowan.

But diplomats say that Russia, which maintains a naval base in Syria, appears determined to resist international pressure over its ally. Russia and China have already vetoed three UN Security Council resolutions on Syria which just talked of possible sanctions.

Neither Russia nor China are sending senior leaders to the UN General Assembly.

On top of the speeches by world leaders, the conflict is expected to dominate a UN Security Council debate Wednesday on links with the Arab League.

The European Union is expected to launch a humanitarian appeal for Syria and the Friends of Syria groups is to meet in New York on Friday.