Thirty countries have pledged to help Iraq fight Islamic State (IS)militants "by all means necessary".
A joint statement by foreign ministers taking part in a major conference in Paris said support would include "appropriate military assistance".
The talks had been called to agree a strategy to combat the group, which controls large parts of Iraq and Syria.
The meeting followed a whirlwind tour of the Middle East by US Secretary of State John Kerry.
Mr Kerry, who attended the summit, has been drumming up support for a plan of action unveiled by President Barack Obama last week.
The CIA estimates that Islamic State has between 20,000 and 31,000 fighters in Iraq and Syria.
The murder of British aid worker David Haines by IS militants, shown in a video released by the group on Saturday, has added momentum to the plans, says the BBC's Lucy Williamson in Paris.