DOHA, Qatar — The Syrian opposition’s major international backers agreed here Saturday to provide ‘‘urgently all the necessary materiel and equipment’’ to rebels fighting the government of President Bashar Assad.
The agreement did not specify what kind of weapons would be sent or which supporters would provide what. But officials attending the Doha conference said that both Saudi Arabia and Qatar are prepared to quickly supply shoulder-launched antiaircraft missiles and armor-piercing shells to be used against Assad’s air force and tanks.
Despite offering a series of pledges of coordination and increased aid in recent months, the rebels’ backers have been divided and inconsistent in acting on them. But officials insisted the new pledge was firm and specific in terms of both quantity and quantity of supplies.
‘‘Something different happened today,’’ Secretary of State John F. Kerry said after a four-hour meeting of foreign ministers from 11 Western and Middle Eastern governments. Because of Assad’s alleged use of chemical weapons and the large-scale intervention of Hezbollah and Iranian militia fighters in Syria’s civil war,’’ he said, ‘‘we have decided that we have no choice . . . but to provide greater assistance.’’
Although the rebels have been receiving arms from Persian Gulf nations, reportedly including a recent influx of surface-to-air missiles from Libya via Qatar, officials said the Doha decision will ensure a continuous, coordinated flow and procedures to ensure the weapons will be kept from Islamic militants.
Officials from participating governments spoke about their closed-door discussions here and in other recent talks on the condition of anonymity.
A European official described Saturday’s decision as a ‘‘collective answer’’ to desperate appeals from General Salim Idriss, head of the opposition’s Supreme Military Council, in the wake of recent rebel defeats.
The session was the fourth time the 11 nations that make up the Friends of Syria group — the United States, Britain, France, Germany, Italy, Egypt, Turkey, Jordan, Saudi Arabia, Qatar, and the United Arab Emirates — have gathered this year. But since their last meeting, barely a month ago in Amman, Jordan, the situation on the ground has turned sharply against the rebels.
First France and Britain, and early this month the United States, said their separate investigations had concluded that Assad had used chemical weapons.
President Obama said a ‘‘red line’’ had been crossed, and that the United States would provide direct military support to rebel fighters. More important, Iranian and Hezbollah intervention inflamed fears that Syria’s civil conflict would spill beyond its borders to become a regional sectarian war.
The escalation of fighting and increasing rebel losses also set back plans to hold peace talks this summer on a post-Assad transition government.
Agreement was not unanimous in the Saturday meeting, and officials said Germany led a small minority opposed to the provision of arms to the rebels on the grounds that it would intensify Syria’s humanitarian crisis and promote, rather than restrain, sectarian war between Sunnis and Shi’ites in the Middle East.
The region’s Sunni powers back the largely Sunni opposition, while Iran and Hezbollah, who support Assad, are Shi’ite, as is Assad’s minority Alawite sect. Kerry on Saturday denounced Assad for inviting Iranian and Hezbollah fighters to fight alongside his troops.