The UN secretary general says that half of Syrias population, some 9.3 million people, are in urgent need of aid.

Ban Ki-moon was speaking at a donor conference in Kuwait promoting the UNs largest ever appeal for a single issue.

The meeting aimed to raise $6.5bn (£4bn) - it had secured $2.4bn in pledges by the end of Wednesday.

Meanwhile, Syrias deputy foreign minister has said Western intelligence agencies have held talks with Damascus on combating Islamist groups in Syria.

The UK government denied having any such co-operation with Damascus.

US state department spokeswoman Marie Harf said the ministers assertion was not true, and that it was "absurd to consider Assad or the regime a partner in countering that threat".

Islamist groups, often made up of foreign fighters, have become increasingly assertive in Syria, clashing with other rebel movements and causing international concern.

On Wednesday, at least 26 people were killed by a car bomb in the northern city of Jarablus, said the UK-based Syrian National Observatory activist group. It blamed the attack on the al-Qaeda-linked Islamic State in Iraq and the Levant (ISIS) and said most casualties were rival rebels.
Starvation

Mr Ban told the Kuwait conference the conflict had "set back Syria years, even decades" and that it was "vital for this region and our world that the burden is shared".

Some 6.5 million people are now displaced inside Syria. More than 2.3 million have registered as refugees outside Syria, many living in camps across the region which are barely coping. There are reports of starvation in towns cut off by fighting.

The UN says more than 100,000 people have died since the uprising began in 2011.

The $2.4bn in pledges secured in Kuwait represent roughly a third of the $6.5bn the UN says it needs for Syria in 2014, though fundraising will continue throughout the year.

Donations include:

Kuwait: $500m
Saudi Arabia: $250m
Qatar: $60m
US: $380m in new contributions
EU countries as a whole: $753m
Norway: $75m
The UK pledged a further $164m bringing its total contribution to $985m
But aid groups say that even when supplies do reach Syria, distribution has become increasingly difficult. They accuse the authorities of deliberately hampering their work in some areas.

Human Rights Watch said Damascus was allowing some shipments in, but had "steadfastly refused to allow aid in from Turkey to reach those in need in northern Syria" and often forced convoys to take circuitous routes.

On Wednesday, UN relief agency Unwra said it had had to withdraw an aid convoy heading to the Palestinian refugee camp of Yarmouk, a few kilometres south of Damascus, when the vehicles were fired upon.

The agency said the authorities had redirected the convoy through areas of intense conflict where jihadi groups are active, Unwras Chris Gunness told the BBC.

The BBCs diplomatic correspondent Bridget Kendall says that for communities trapped by the fighting, what is needed is not so much more money, but an agreement on local ceasefires or humanitarian corridors.

But it is by no means clear the fragile peace process supposed to be launched at an international conference in Geneva next week can make that happen, she adds.

The main opposition alliance, the National Coalition, has still not decided whether to take part in the talks, fearing participation could undermine its credibility with the anti-government opposition inside Syria.

Correspondents say the growing disarray of the opposition is frustrating the West and bolstering the confidence of the Syrian government.

No alternative

Western states have insisted that President Bashar al-Assad is responsible for the conflict and must stand down.

But in a recent interview with the BBC, Syrias deputy foreign minister said Western intelligence agencies had visited Damascus seeking co-operation on combating radical Islamist militants in Syria.

Mr Mekdad said there was a schism between what Western politicians were saying and what security officials were doing in practice, and that many had finally understood there was no alternative to the leadership of President Assad.

The BBCs chief international correspondent Lyse Doucet said informed sources had confirmed meetings between Western and Syrian intelligence officials.

Khaled Saleh, spokesman for the National Coalition, told the BBC that if the reports were true, "it would show a clear contradiction between the words and actions of the (Western-led) Friends of Syria group".

The Friends of Syria is a group of countries set up to support the Syrian opposition, with 11 states in the region and in the West comprising its "core group".

Mr Saleh said it was the Syrian opposition, not the government, that was combating "terrorist groups" such as the Islamic State in Iraq and the Levant (ISIS) which he insisted was "organically linked" to the Mr Assads government.

BBC