A Muslim activist and lawyer in the U.K. is calling on Muslims worldwide to burn U.S. flags outside American embassies on Sept. 11. The activist, according to CBS news, is considered a radical, and says his “international burn the Stars and Stripes Day” is in “direct retaliation” against pastor Terry Jones and his Florida church’s plan to burn the Koran on the same day.

The man calling for the mass burning is Anjem Choudary, former leader of the banned hardline Islamic group Islam4UK. According to CBS, Choudary regularly organizes demonstrations in Britain calling for the implementation of Islamic law.

The report also says that the State Department has issued a warning to all embassies to prepare for possible backlash should the Koran burning take place as planned on Saturday.

General David Petraeus, Secretary of State Hilary Clinton, and others have spoken out against the planned Koran burning. Petraeus has said that it will endanger U.S. troops abroad, while Glenn Beck has said that “burning the Koran is like burning the flag or the Bible.”

UPDATE:

Meanwhile, an Afghan cleric today warned that U.S. troops in the country’s north would face large protests if Jones proceeds with his planned Koran burning. Yahoo News reports that Abdul Hadi Rostaqi, a member of the cleric council in Afghanistan’s largely peaceful Balkh province, said if the burning goes ahead, “a big protest will be held” in the provincial capital Mazar-i-Sharif next Monday, and that NATO-led troops stationed in the city would be the primary target.

The report also notes that about 200 people marched and burned a U.S. flag in the central Pakistani city of Multan, quoting one protester’s sign as saying, “If Quran is burned it would be beginning of destruction of America.”

Iran’s Foreign Minister Manouchehr Mottaki also warned of “reactions by the world’s Muslims as well as followers of other religions.”