The Friends of Syria meeting in Istanbul says that it recognizes the Syrian National Council as a legitimate representative of all Syrians.
In a final communique concluding its one-day meeting in Istanbul on April 1, the conference also says the window for Syrian President Bashar al-Assad to implement the commitments it agreed to under a UN-Arab League peace deal presented by envoy Kofi Annan is not open ended.
The communique calls on Annan to set a timeline for next steps, including when to return to the UN Security Council.
And the communique calls on Syrian government forces to disobey unlawful orders targeting civilians.
Representatives of more than 60 Western and Arab countries attended the meeting in Istanbul to step up pressure on Damascus to end its yearlong crackdown on the opposition.
Russia, China, and Iran stayed away.
During the conference, U.S. Secretary of State Hillary Clinton urged members of Assad's government to halt operations targeting civilians, or face "serious consequences."
She also said the U.S. is providing communications gear to the Syrian opposition and is urging it to develop a "political action plan."
"People have been working very hard to try to figure out ways to help those inside Syria who are bearing the brunt of the brutality of the Assad regime," Clinton said.
"We are painfully aware how brutal the actions by the regime had been. And the Syrian National Council has been working hard to organize different Syrians behind a unified approach. Because until recently, it was hard to know who to help. There was not the kind of organized effort."
The head of the opposition Syrian National Council (SNC) announced on April 1 that the group would pay the salaries of all rebels fighting the regime of President Assad.
SNC President Burhan Ghalioun told reporters in Istanbul that "the SNC will take charge of the payment of fixed salaries of all officers, soldiers, and others who are members of the Free Syrian Army."
Syrian activists say at least 16 people were killed on April 1, including eight soldiers who died during ambushes and gun battles in the east, northwest, and near Damascus, monitors said.
The UN-Arab League plan calls for an end to fighting, talks between the government and the opposition, and access for international aid agencies.