Arab foreign ministers on Sunday agreed sweeping sanctions against Damascus to punish President Bashar al-Assad's regime for failing to halt a deadly crackdown on protests, as the death toll in Syria kept on climbing.
As another 23 civilians were reported dead in Syria, the 22-member Arab League announced an immediate ban on transactions with the Syrian government and central bank and a freeze on Syrian government assets in Arab countries.
Further measures including a ban on Syrian officials visiting any Arab country and the suspension of flights are to be implemented at a date fixed at a meeting next week.
Syrian state television reacted with a terse statement saying the Arab League's action against a member state was "an unprecedented measure" as hundreds of people gathered in Damascus to protest against the measures.
Foreign Minister Walid Muallem, who in a letter to the pan-Arab bloc ahead of the vote accused the organisation of seeking to "internationalise" the Syrian crisis, prepared to hold a news conference on Monday.
The sanctions, announced in Cairo by Qatari Prime Minister Sheikh Hamad bin Jassim al-Thani, are the first time the organisation has imposed such harsh economic measures against another country in the region.
"We hope that (the Syrian regime) puts an end to the massacres so that this resolution (authorising sanctions) is not put into force," said Sheikh Hamad, but he added that "the signs are not positive."
He also called for "an end to the massacres, the freeing of prisoners and the withdrawal of tanks" from Syrian cities.
The Local Coordination Committees, an umbrella group of Syrian activists, welcomed the move but warned that Damascus could get around the sanctions.
"Economic sanctions will have no impact on the Syrian regime unless there is a mechanism by which the implementation of sanctions can be strictly monitored and leave no opportunity for their circumvention," it said.
The LCC noted in a statement that Iraq and Lebanon, neighbours who have close economic ties with Syria, had reservations about the sanctions.
"The sanctions leave open the opportunity for the regime to commit fraud and strip the sanctions of any substance, thereby prolonging the suffering of the Syrian people at the hands of an oppressive and brutal regime, and due to the sanctions' longer term impacts," it said.
The activists also urged the Arab League "to exert all necessary pressure and make every possible effort in response to the Syrian people's choice to topple the regime."
Nineteen Arab League members voted for the sanctions, but Iraq abstained and said it would refuse to implement them, while Lebanon "disassociated itself," Sheikh Hamad said. Syria is a suspended member.
Iraqi Foreign Minister Hoshyar Zebari, whose country thrives on trade with Syria, said ahead of Sunday's vote it was "not possible" to impose sanctions on Assad's regime.
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According to Syria's bureau of statistics, 52.5 percent of all Syrian exports went to Arab countries in 2009 while 16.4 percent of imports came from Arab nations.
Iraq tops the list of importers, buying up 31.4 percent of outgoing Syrian goods.
Nasser Judeh, the foreign minister of Jordan whose imports travel by land across Syrian territory, also expressed concerns after the vote which his country endorsed.
"The impact of such decisions on Arab countries, particularly neighbours (of Syria)... must be taken into consideration," he said.
But the impact of the Arab sanctions is expected to be crippling for Syria itself which already faces a raft of EU and US measures even without Iraq or Lebanon's participation.
In London, British Foreign Secretary William Hague praised the Arab League's move.
"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 said in a statement..
Turkish Foreign Minister Ahmet Davutoglu, who attended the Arab League meeting, said: "Nobody can expect Turkey and the Arab League to remain silent on the killings of civilians and the Syrian regime's increasing oppression of innocent people."
Earlier this month Ankara hit its former ally Syria with energy sanctions and threatened more moves after Damascus defied an Arab League ultimatum to accept observers and end its lethal crackdown.
On Sunday the violence showed no sign of abating.
Activists said at least 23 civilians were killed, including seven in the flashpoint region of Homs that has been under siege for several weeks.
The UN estimated earlier this month that more than 3,500 people have been killed in the repression since protesters first took to the streets in mid-March.
An analyst said the sanctions will not only cripple the regime but could persuade business figures to abandon it.
"The sanctions further isolate everyone at the top," said Angus Blair from the Egypt-based investment bank Beltone Financial.
"It makes it very difficult for figures in Syria to be seen to be close to the regime," he said.