WASHINGTON // Kofi Annan, the United Nations-Arab League special envoy for Syria, yesterday tendered his resignation after failing to convince Syria's warring sides to accept his peace plan.
At a news conference in Geneva, Mr Annan blamed the UN Security Council for "finger pointing and name calling" when the Syrian people "desperately need action".
The announcement came 17 months after the start of political upheaval in Syria and as the conflict passed a critical threshold.
In addition to covert military aid, Washington has set aside US$25million (Dh91.8m) for communications equipment and medical supplies for the opposition and yesterday announced an extra $12m in humanitarian aid for Syrian civilians.
Alongside Saudi Arabia, Qatar and Turkey, the moves put a US president running for re-election squarely in the middle of the uprising to unseat Mr Al Assad.
Syria's rebels yesterday shelled an airport near Aleppo in the first reported instance of the Syrian opposition using heavy weaponry seized from government forces. The battle for Syria's largest city has intensified in recent days.
With the resignation of Mr Annan, the likelihood of any negotiated outcome to fighting that by some estimates has claimed more than 20,000 lives has receded even further.
Speaking in Geneva, the former UN secretary general said the increasing militarisation in Syria and the "clear lack of unity" in the Security Council had "fundamentally changed the circumstances for the effective exercise of my role".
He blamed both sides in the conflict, but said the problems were "compounded by the disunity of the international community".
Mr Annan will retain his position until the end of August, but the UN secretary general Ban Ki-moon said he was already in discussions with the Arab League to find a successor.
"Kofi Annan deserves our profound admiration for the selfless way in which he has put his formidable skills and prestige to this most difficult and potentially thankless of assignments," Mr Ban said in a statement.
According to reports in the Russian media, Russia's president Vladimir Putin said Mr Annan's resignation was a "great shame".
Syrian opposition factions were also due to meet yesterday in Qatar in what was billed as the most comprehensive bid to date to bring together Syrian opposition groups and present a credible alternative to Mr Al Assad's regime.
Syria's many and varied opposition groups have had a hard time presenting a united front. There have been reports in recent weeks of battles on the ground between some factions, and there were signs of more disunity on Wednesday when the head of the Free Syrian Army denounced leaders of a new political opposition coalition as "opportunists".
The Council for the Syrian Revolution was announced on Tuesday in Cairo and brings together 70 exiled Syrian activists under Haitham Al Maleh, a leading opposition figure. But Riad Al Asaad, the head of the FSA, on Wednesday told Al Arabiya satellite station that the Council's formation of a transition government was an attempt "to ride over our revolution and trade with the blood of our martyrs".
Continued divisions notwithstanding, the US administration is getting ever more involved.
On Wednesday, Reuters reported that Mr Obama had signed a secret order that gives broad permission to the CIA and other US government agencies to aid the Syrian opposition.
US officials continue to insist that support for the rebels is strictly "non-lethal". But Reuters last week also reported the existence of a secret rebel "control centre" in Turkey, less than 100 kilometres from the Syrian border and near a major US air force base, where US military and intelligence agencies maintain a substantial presence.
It is not clear when the order was signed. But with the rebels holding out better than expected in Aleppo, and the Syrian regime showing signs of desperation, it suggests that the US administration is sensing the approach of an endgame and wants to help speed it along, said Wayne White, a former deputy director of intelligence at the US State Department and now a scholar at the Middle East Institute, a Washington-based think tank.
"When you see a situation maybe approaching a tipping point, you want to tip it," Mr White said.
Mr White suggested that the battle for Aleppo was turning out to be a crucial moment in the fighting.
On Wednesday, President Assad had urged his army to "step up" its efforts in a battle he said would "determine the destiny of our people and the nation's past, present and future".
His message betrayed a certain amount of desperation, said Mr White.
"That seemed like a desperate appeal to his forces implying that they were teetering on the edge of possibly losing control of the situation."
As yet unconfirmed reports also suggest Syrian rebels are now receiving surface-to-air missiles from Turkey. If true, this also suggests a decision had been reached among US allies in the region that it was "time more risks were taken", Mr White said.
Should a decisive moment be near, the US administration will also be keen to have some leverage over what comes next. Its support for the Syrian rebels, overt or covert, will likely prove crucial,
The US State Department yesterday released a breakdown of the more than $76 million in humanitarian aid the US supplies Syria and neighbouring countries, including aid to the World Food Programme and the United Nations High Commissioner for Refugees.
* With additional reporting from Associated Press