A bomb exploded in southern Afghanistan's largest city of Kandahar on Monday, killing at least one person and wounding two, Afghan officials said. It followed the killing of a local government leader near the country's volatile eastern border region earlier in the day.

The Kandahar bomb went off at the city's customs house during a visit by NATO troops, police chief Khan Mohammad Mujahid said. He said an Afghan interpreter was killed, and at least two people were wounded in the attack.

The government building is used by residents to clear customs paperwork on imported items. Visitors typically must undergo pat-downs to enter, raising questions about security procedures at the facility.

Mujahid said the bomber was able to enter the building before detonating the bomb. Zalmai Ayubi, the spokesman for the Kandahar provincial governor, said only that the explosion occurred near the building. Conflicting reports are common in the immediate aftermath of bombings.

NATO spokesmen in Kabul said they had reports of the blast and were investigating.

Kandahar is located in the Taliban's traditional southern stronghold. A suicide car bomb struck outside the house of the police chief in the city Friday, wounding at least two people.
The Taliban claimed responsibility for Monday's attack within minutes of the blast. Taliban spokesman Qari Yousef Ahmadi said a team of two suicide attackers was involved.
Earlier in the day, gunmen killed the acting chief of Khost province's Bak district on his way to work. The official, identified as Sayed Mohammad, was shot by four men wearing Afghan national army uniforms as he was driving from his home to the office at about 9 in the morning, provincial officials said.

The daytime shooting is the latest deadly attack in Khost, the scene of numerous insurgent strikes, including a high-profile suicide bombing at a remote CIA outpost in late 2009. It is located along the mountainous border region with Pakistan where the Haqqani network, a group with ties to the Taliban and al-Qaida, is known to operate.

The Taliban also claimed responsibility for that attack. Zabihullah Mujahid, a spokesman for the group, said Mohammad was targeted because of his collaboration with foreign troops.
U.S. and NATO commanders say they are making progress in the fight against the Taliban and its allies despite the continued violence.

NATO said it and Afghan security forces detained several suspected insurgents during a raid targeting a Haqqani network leader elsewhere in Khost province on Sunday. The international force didn't identify the leader, who it said is responsible for coordinating bombings against Afghan and coalition troops and teaching insurgents how to rig houses with explosives.

The U.S. hopes to solidify gains against insurgents as it prepares to begin drawing down forces in July. NATO aims to hand over responsibility for Afghanistan's security to local forces and pull all its troops out by 2014.

A New York University report released Monday by researchers based in the Taliban stronghold of Kandahar argues that the group's older leadership is finding it increasingly difficult to control insurgency efforts as their authority wanes.

The report's authors, Alex Strick van Linschoten and Felix Kuehn, say Al-Qaida and the Taliban remain separate groups with distinct objectives despite their shared opposition to U.S.-led forces in the region. But as the Taliban chain of command weakens, they say lower-level leaders are becoming more financially independent and open to manipulation by Al-Qaida.