Washington warned on Tuesday of a potential upsurge in "terrorist attacks" targeting American citizens or interests abroad following the death of al-Qaeda leader Ayman al-Zawahiri, who was killed by the United States in a of an air strike overnight from Saturday to Sunday.

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• Read also: The United States kills the leader of Al-Qaeda, Ayman al-Zawahiri

"The State Department believes there is an increased risk of anti-American violence following the death of Ayman al-Zawahiri on July 31, 2022," US diplomacy said in a statement.

"Current intelligence suggests that terrorist organizations continue to plan terrorist attacks against U.S. interests in multiple regions around the world," the statement added.

“These attacks can take many forms, including suicide operations, assassinations, kidnappings, hijackings and bomb attacks.”

Egyptian Ayman al-Zawahiri, who took over as head of al-Qaeda after the death of Osama Bin Laden in 2011, was killed on his balcony overnight from Saturday to Sunday in Afghanistan by a US drone strike , US President Joe Biden announced on Monday live.

Untraceable for more than ten years, Ayman al-Zawahiri, 71, was considered one of the masterminds of the attacks of September 11, 2001, which killed nearly 3,000 people in the United States.

Taliban spokesman Zabihullah Mujahid condemned an "air attack" carried out using "American drones" early Tuesday morning, without mentioning any casualties or mentioning Zawahiri's name.

"American citizens are strongly encouraged to maintain a high degree of vigilance" when traveling abroad, the State Department said.