A Libyan militant is facing trial in the United States in the attack on a U.S. diplomatic post in Libya that killed U.S. Ambassador Chris Stevens and three other Americans.

President Barack Obama says Ahmed Abu Khattala will face ``the full weight of the American justice system.''

Khattala is a senior leader of the Benghazi branch of the terror group Ansar al-Shariah. The Pentagon says he was captured by American forces on Sunday, and he's now being held in an undisclosed location outside of Libya.

Last year, the U.S. filed charges against him and a number of others in the attack. Officials say he could face the death penalty.

Until now, no one had been arrested in the attack in which a group of militants set fire to the U.S. diplomatic mission in Benghazi.

A U.S. official says the operation that captured Abu Khattala had been in the works for a long period of time, and was carried out by U.S. special operations forces.

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