BAGHDAD — The U.N.'s top Iraq envoy today condemned the killing of two Christian sisters in Mosul, the volatile northern city where Christian residents were starting to return a month after extremist threats forced thousands to flee.

Gunmen killed the sisters Wednesday as they were waiting in front of their house for a ride to work, police said. Their mother was wounded in the attack, and the U.S. military said the family's house was destroyed by bombs planted inside.

U.N. special representative Staffan de Mistura "expressed his shock and outrage at the continued targeting and killing of religious minorities" in a statement.

The attack came after about 13,000 Christians fled Mosul, an ethnically mixed city of Kurds, Christians and Arabs, following a spate of threats and killings last month. Sunni insurgents are believed to be behind the campaign to drive them out.

KABUL, Afghanistan — A suicide bomber rammed his car into a U.S. military convoy as it was passing through a crowded market in eastern Afghanistan today, killing at least 20 civilians and an American soldier, officials said.The attack outside Jalalabad, the capital of the eastern Nangarhar province, also wounded 74 civilians, said Ajmal Pardes, a provincial health official.Separately, an explosion in southern Afghanistan on Wednesday killed two NATO soldiers, the military alliance said in a statement, without disclosing the soldiers nationalities.The bomber struck the convoy near a crowded market in the Bati Kot district, where people were trading sheep, cows, goats and other animals, said Ghafoor Khan, the spokesman for the provincial police chief.Lt. Cmdr. Walter Matthews, a U.S. military spokesman, said at least 20 civilians and a U.S. soldier were killed. The soldier's death brings the number of U.S. troops killed in Afghanistan to at least 148, the highest number of troop deaths per year since the U.S.-led invasion in 2001.

TEHRAN, Iran — Iran said it successfully test-fired a new generation of long range surface-to-surface missile on Wednesday — one that could easily strike Israel and as far away as southeastern Europe with greater precision than earlier models.The Sajjil is a solid fuel high-speed missile with a range of about 1,200 miles, Defense Minister Mostafa Mohammed Najjar said on state television.Solid-fuel missiles are more accurate than the liquid fuel missiles of similar range currently possessed by Iran. The country has had a solid-fuel missile with a shorter range — the Fateh, able to fly 120 miles — for several years.