A suicide bomber has killed the mayor of Afghanistan's southern city of Kandahar, the latest in a series of high-profile assassinations of key allies of President Hamid Karzai.

The Taliban claimed responsibility for Wednesday's attack that killed Mayor Ghulam Haider Hamidi and wounded at least one bystander. A Taliban spokesman said the attack was to avenge the deaths of two children and a woman allegedly killed during the city's recent demolition of illegally constructed homes.

Witnesses say Hamidi was meeting with constituents in the city about the land dispute at the time of the attack. Local authorities have not yet determined the motive or the identity of the attacker, who apparently had hidden the bomb in his turban.

Hamidi escaped previous attempts on his life. Last year, two of his deputy mayors were killed in attacks.

Hamidi's death follows last week's targeted killing in Kabul of a member of parliament who was also a senior advisor to President Hamid Karzai. And earlier this month in Kandahar, a trusted bodyguard shot and killed President Karzai's half-brother, Ahmad Wali Karzai.

The Taliban claimed responsibility for all the attacks.

Analysts say the death of President Karzai's half-brother, who was an important power broker in Kandahar, has left a significant power vacuum in the area. Kandahar is the birthplace of the Taliban and an important stronghold for the militant group in the south, where it remains entrenched despite sustained coalition military operations against them.

Following Wednesday's killing, President Karzai and the international coalition issued separate statements condemning the violence.

U.S. Ambassador to Afghanistan Ryan Crocker also condemned the attack, saying the apparent motive for the assassination is another indication of the challenges the country faces.

The new ambassador also noted that the targeted killings could be a sign of “significant organizational weakness” in the Taliban, highlighting their inability to mount more organized attacks.

Hamidi was an American citizen who lived in the United States for several years before returning to Afghanistan. He had been mayor of Kandahar city since 2007 when he was appointed to the post by President Karzai, a longtime ally.

The increased violence comes as Afghans begin taking security control of parts of the country from U.S. and NATO-led forces.

Some 33,000 American forces are set to leave Afghanistan by September of 2012. Last week, the first seven areas of Afghanistan were transitioned from NATO control to Afghan forces. Most foreign combat troops are set to leave Afghanistan by the end of 2014.