Western and Arab governments have pledged more political and material support for the civilian Syrian opposition and called for an immediate halt to arms supplies to the Assad government.
"John Kerry and Moaz al-Khatib turned in an impressive double-act after the Rome Friends of Syria meeting.
There’s a new mutual confidence and clearly a new working relationship.
In the two-year "safe window" of President Barack Obama's second term, Washington is now prepared to do a lot more for the Syrian opposition. Weapons (via Saudi largesse) behind the scenes, and up-front aid directly to the Syrian Military Councils.
Al-Khatib read the mood well, returning repeatedly to the ballistic missile attacks on Aleppo as proof of the regime’s unmatched "brutality".
And laying out five commonsense goals – humanitarian corridors, unity of the country, negotiations, a brake on Russia's weapons to the regime and help for refugees."
A final statement after a meeting of the Friends of Syria group in Rome added: "The regime must immediately stop the indiscriminate bombardment against populated areas which are crimes against humanity and cannot remain unpunished".
"The ministers pledged more political and material support to the (Syrian National) coalition as the sole legitimate representative of the Syrian people and to get more concrete assistance (into) Syria," it said.
They gave no detail of what kind of support would be supplied.
The statement also deplored "the unabated arms supply to the regime by third countries".
Speaking after talks with the Syrian opposition and mainly European and Arab countries supporting them, John Kerry, the US secretary of state, said his country would provide Syrian opposition with $60m in new aid and work with rebel fighters.
The US plans for the first time to provide non-lethal aid, including food rations and medical supplies, to opposition fighters battling the Syrian government and it will more than double aid to the civilian opposition, the US secretary of state said at a joint press conference with Syria Opposition leaders.
Bashar al-Assad lost his legitimacy long ago, and has lost his power, Kerry said.
The meeting came ahead of an important meeting of the Syrian National Coalition on Saturday in Istanbul, Turkey where the umbrella opposition group is to elect a prime minister and government to run parts of Syria seized from Assad's control.
The opposition - which initially pledged a boycott - participated in the 11-nation meeting on Thursday after the US and Britain promised specific offers of help.
In Paris, as part of a European tour on Wednesday, Kerry made it clear Washington was ready to step up its support for the opposition.
"We are examining and developing ways to accelerate the political transition that the Syrian people seek and deserve, and that is what we will be discussing in Rome," Kerry said.
Meanwhile, a senior UN official has told the Security Council that the total number of Syrian refugees is likely to pass one million in less than a month.
Antonio Guterres, the UN High Commissioner for Refugees, said the UN agency as of Tuesday had registered 936,000 Syrians across the Middle East and North Africa, nearly 30 times as many people as April last year.
The UN humanitarian chief has said that the growing number of Syrians fleeing the country's conflict is outstripping the international community's ability to help.
Valerie Amos told reporters after briefing the Security Council that "this is a crisis that is completely stretching our capacity".
She said she was extremely concerned about the rising cost, noting that the UN had received only $200m of the more than $1.5bn pledged for Syria at a January 30 donor's conference in Kuwait.
The $1.5bn was supposed to cover humanitarian needs in Syria for six months but that projection from the end of the year is already out of date, she added.