BEIRUT (AP) – In an unprecedented move against an Arab nation, the Arab League on Sunday approved economic sanctions on Syria to pressure Damascus to end its deadly suppression of an 8-month-old uprising against President Bashar Assad.

But even as world leaders abandon Assad, the regime has refused to ease a military assault on dissent that already has killed more than 3,500 people. On Sunday, Damascus slammed the sanctions as a betrayal of Arab solidarity and insisted a foreign conspiracy was behind the revolt, all but assuring more bloodshed will follow.

The sanctions are among the clearest signs yet of the isolation Syria is suffering because of the crackdown. Damascus has long boasted of being a powerhouse of Arab nationalism, but Assad has been abandoned by some of his closest allies and now his Arab neighbors. The growing movement against his regime could transform some of the most enduring alliances in the Middle East and beyond.

At a news conference in Cairo, Qatari Foreign Minister Hamad bin Jassim said 19 of the League's 22 member nations approved a series of tough punishments that include cutting off transactions with the Syrian central bank, halting Arab government funding for projects in Syria and freezing government assets. Those sanctions are to take effect immediately. Other steps, including halting flights and imposing travel bans on some, as-yet unnamed Syrian officials, will come later after a committee reviews them.

``The Syrian people are being killed but we don't want this. Every Syrian official should not accept killing even one person,'' Bin Jassim said. ``Power is worth nothing while you stand as an enemy to your people.'' He added that the League aims to ``to avoid any suffering for the Syrian people.''

In London, British Foreign Secretary William Hague on Sunday praised the Arab League's move to impose sweeping sanctions on Syrian President Bashar al-Assad and called for the UN to back up the bloc's decision. ''We welcome the Arab League's leadership in seeking an end to the horrific violence in Syria,'' said Hague in a statement issued by the Foreign Office (FCO) Sunday.

''Today's unprecedented decision to impose sanctions demonstrates that the regime's repeated failure to deliver on its promises will not be ignored and that those who perpetrate these appalling abuses will be held to account,'' he added.

Iraq and Lebanon - important trading partners for Syria - abstained from the vote, which came after Damascus missed an Arab League deadline to agree to allow hundreds of observers into the country as part of a peace deal Syria agreed to early this month to end the crisis.