The United Nations has warned that up half the Syrian population will need will need humanitarian aid by the end of the year and launched what it said was its largest appeal in history.
The UN is seeking more than $US5 billion in aid though officials admit they may struggle to raise the record sums they are asking for.
UN emergency relief co-ordinator Valerie Amos said the number of people displaced in Syria more than doubled between January and April.
At present more than 1.5 million Syrians are refugees and the UN estimates expects the number to leap to nearly 3.5 million by the end of the year. In all, it says, more than 10 million Syrians will need help.
UN children's agency Unicef says as many as four million children need urgent assistance.
The BBC reports governments were criticised for being slow to commit funds to the previous UN target of $US1.5 billion for the first six months of this year, but UN officials say $US1.2 billion has now been committed.
In Geneva on Friday the UN said it had revised up the amount of funding needed because of the worsening security situation in Syria.