Kuwait: Donors gathered in Kuwait Wednesday in a major fundraising drive for 13 million Syrians affected by war following a record UN appeal for $6.5 billion.

As Syrians shivered through their third winter of conflict, delegates from 69 nations and 24 international organisations were to attend the one-day event chaired by UN chief Ban Ki-moon.

With fighting on the ground as intense as ever and the prospects of a negotiated solution still dim, rights and aid groups said urgent funds were needed.

“The continuing violence in Syria has sparked one of the biggest humanitarian crises in recent history,” Amnesty International said in a statement Tuesday.

“The world's response to the Syria crisis so far has been woefully inadequate,” Amnesty said, ahead of the Second International Humanitarian Pledging Conference for Syria.

The UN is looking for $2.3 billion to support 9.3 million people inside Syria and $4.2 billion for Syrian refugees, expected to nearly double to 4.1 million by year's end.

Amnesty said the world community must act now to end the suffering of Syrian civilians, many of whom face severe shortages of food supply, medical care and adequate shelter.

It also called on the Syrian government to lift blockades on the civilian population in opposition held towns and areas.

Non-government charity organisations meeting in Kuwait on Tuesday pledged $400 million for Syrians, with Kuwait promising $142 millions of the total.

The European Union offered an extra 165 million euros ($225 million) of aid, EU Aid Commissioner Kristalina Georgieva told AFP, raising the union's total contributions to 2.0 billion euros ($2.74 billion).

“We see the humanitarian situation going from bad to worse, we have seen no improvement,” Georgieva said of the conflict, which is thought to have killed more than 130,000 people.

The UN has described the $6.5 billion Syria appeal as the largest ever in its history for a single humanitarian emergency.

At the first donors' conference in Kuwait last January, participating nations pledge $1.5 billion, 75 percent of which was delivered, according to a Kuwaiti official.

In a research released Wednesday, Aid group Oxfam said Russia, Japan and South Korea contributed much less than their fair share to the Syrian crisis.

US Secretary of State John Kerry arrived in Kuwait Tuesday following talks in Paris and Rome aimed at preparing the so-called January 22 “Geneva II” peace talks.

An official speaking to reporters travelling with Kerry said Washington had “given more than $1.3 billion to date, of which 700 million has been inside Syria”.

“The US at this point is the largest single donor to the Syrian crisis, and we focused quite a bit of that on ensuring that assistance reaches as many people as we can inside,” another official said.

The World Food Programme said it was stepping up food aid, describing the situation as its worst humanitarian crisis.

“This is the worst humanitarian crisis that we have seen in decades, with every day more vulnerable Syrians pushed into hunger,” said WFP Syria emergency coordinator Muhannad Hadi last month.

According to aid agencies, 10.5 million Syrians are food insecure, more than a million children under five suffer from acute or severe malnutrition, about half the population has no access to adequate water sources or sanitation and 8.6 million have insufficient access to healthcare.

Lebanon is currently home to the largest number of refugees with 905,000, followed by Jordan with 575,000, Turkey 562,000, Iraq 216,000 and Egypt 145,000.

By the end of 2014, these numbers are estimated to rise to 1.65 million in Lebanon, 800,000 in Jordan, 1.0 million in Turkey, 400,000 in Iraq and 250,000 in Egypt.