At least 100,000 people have attended an angry rally against any war with Iraq at a stadium in the Egyptian capital, Cairo.
Many protesters were students
"With our blood, with our souls, we will sacrifice ourselves for you, Iraq," the crowd chanted as they brandished thousands of placards backing Baghdad and denouncing US President George W Bush and Israel.
The opposition rally was sanctioned by the government, a key ally of Washington, though members of the banned Muslim Brotherhood were among the speakers.
The BBC's Simon Wilson, who was at the event, reports that it is one of the biggest public protests against American and British policy yet seen in the Arab world.
It comes as leaders from across the Arab region prepare for a summit in the Egyptian resort of Sharm el-Sheikh at the weekend which is expected to focus on Iraq.
By allowing this large, set-piece anti-war protest, our correspondent says, it seems the government is hoping to show it is sensitive to the undoubted anger many Egyptians feel about the threat of war.
Security at Cairo Stadium was discreet for the event, which was organised by a coalition of opposition groups.
Despite the ban on the Muslim Brotherhood, many people were privately speaking of their support for the group and its call for a jihad (or holy war) in defence of Iraq and the Palestinian territories, our correspondent reports.
The Sudanese protesters delivered a letter to the local UN office
Demonstrations are normally banned in Egypt under emergency laws in force since 1981 but the authorities have tolerated recent rallies on university campuses and in mosque compounds.
The ruling National Democratic Party is, for its part, believed to be planning a mass march in Cairo in support of Iraq and the Palestinians which it hopes will attract half a million people.
The march is expected to take place next week, newspapers say.
In Khartoum, the Sudanese capital, at least 100,000 people attended an anti-war rally on Wednesday.
Sudan is also a member of the Arab League, assembling in Egypt for this weekend's summit.