Afghan authorities say militants launched an hours-long assault using explosives and gunfire on government buildings in the volatile southern province of Uruzgan Thursday, one of the deadliest attacks to hit the country in recent months.

The Taliban claimed responsibility for the coordinated attack, which killed at least 19 people and wounded 37 others. The group said it used a team of six suicide bombers to strike at the governor's house, police headquarters and the base of a militia commander who provides security to NATO convoys.

A NATO spokesman said the international coalition sent reinforcements, including air support, to help the Afghan forces repel the assault.

Medical officials say the casualties include civilians, among them children. The British Broadcasting Corporation also said one of its part-time reporters, a 25-year-old local man, died in the attack.

Thursday's violence is the latest setback to security in southern Afghanistan, coming after a series of high-profile assassinations of key allies of President Hamid Karzai.

A day earlier, the Taliban claimed responsibility for the suicide bombing that killed the mayor of Kandahar city. The mayor's death follows last week's targeted killing in Kabul of a senior advisor to President Karzai. And earlier this month in Kandahar, a trusted bodyguard shot and killed President Karzai's half-brother, Ahmad Wali Karzai.

Throughout the violence, the international coalition has pressed ahead with transferring security control to Kabul. Last week, NATO transferred the first seven areas of Afghanistan to the control of Afghan forces.

About 33,000 American troops are set to leave Afghanistan by September of 2012 with all foreign combat troops scheduled to exit the war-torn country by the end of 2014.