Ammon News - CAIRO (Reuters) - Arab League ministers will pass a resolution blaming Syrian President Bashar al-Assad for last week's chemical weapons attack in Damascus when they meet in Cairo next week, League officials said on Wednesday.

The states' permanent representatives at the League had already explicitly blamed Assad on Tuesday for the attack, which killed hundreds of civilians, in a step that provided regional political cover for a possible U.S.-led military strike on Syria.

A senior U.S. official said planning was under way for possibly several days of attacks by several countries, likely to include its NATO allies France and Britain, to punish Assad.

The higher-level endorsement by the Arab foreign ministers at their meeting on September 2-3 is being pushed by Saudi Arabia and Qatar, which both back anti-Assad rebels in Syria's civil war, as well as Qatar, a non-Gulf official at the League said.

Syria's neighbors Iraq and Lebanon, along with Algeria, are likely to oppose or abstain from condemning Syria, as they have on similar resolutions in the past. Syria itself is suspended from the League.

"The Arab foreign ministers will affirm the full responsibility of the Syrian regime for the chemical weapons' attack that took place in Eastern Ghouta (on the outskirts of Damascus)," a representative of a Gulf state in the League told Reuters.

"We will also ask for those responsible for the attack to be taken to the International Criminal Court," he added.

The non-Gulf Arab League source confirmed the Gulf official's remarks.

"The world must see the Arab states seriously condemning Assad's use of chemicals and calling for his punishment," he said.

He also called on the U.N. Security Council to adopt tougher sanctions on Syria and urged Russia and China, Assad's backers in the council, not to block any council resolution proposing action against Assad.

Syria's civil war has split the region broadly along sectarian lines.

Shi'ite Muslim Iran, and its allies in Lebanon and Iraq, support Assad. The Sunni-led Gulf Arab states, led by oil giant Saudi Arabia and influential Qatar, have backed the mainly Sunni Muslim rebels, many of whom are Islamist militants.