CAIRO (Update 3) - The Arab League suspended Syria and called on its army to stop killing civilians in a surprise move on Saturday that turned up the heat on President Bashar al-Assad. The League will impose economic and political sanctions on Syria's government and has appealed to member states to withdraw their ambassadors, said Qatar's Prime Minister Sheikh Hamad bin Jassim al-Thani. It will also call a meeting of Syrian opposition parties, he said. "We were criticised for taking a long time but this was out of our concern for Syria," Sheikh Hamad told reporters at the League's headquarters in Cairo. "We needed to have a majority to approve those decisions." Syria's representative at the Arab League said the decision was "not worth the ink it was written with". Hopes among Western powers that Assad would be isolated by his Arab neighbours were repeatedly dashed until now. Some Arab leaders have been reluctant to turn against one of their peers given their own restive populations, Middle East diplomats say. But Assad has pressed ahead with the crackdown on protesters against his rule despite an Arab peace plan brokered on Nov. 2. The United Nations says more than 3,500 people have been killed in seven months of violence. Activists said at least six people were killed in Syria on Saturday. "We are calling all Syrian opposition parties to a meeting at the Arab League headquarters to agree a unified vision for the transitional period," said Sheikh Hamad, who is also Qatar's foreign minister. He said the suspension of Syria from the regional body would take effect on Nov. 16, but did not detail the sanctions. "We ask the Arab Syrian Army to not be involved in the violent actions and killing of civilians," Sheikh Hamad said, quoting from an Arab League statement. Syria's Arab League representative, Youssef Ahmed, said suspending Damascus violated the League's charter because it could only be done by consensus at a summit of Arab leaders. It was clear that "orders were issued to them from the United States and Europe to hasten a decision against Syria," Ahmed told Syrian state TV. Syrian TV reported a demonstration outside the Qatar embassy in Damascus, while Assad's opponents hailed the League's new resolve. "This gives a lot of strength to the position of the Syrian National Council. This is now an Arab position," said Basma Qadmani, a member of the executive committee of the Syrian National Council, the most prominent opposition group.