Two bombs have killed at least nine people and wounded more than 70 others inside a gated Afghan complex near Kandahar linked to the family of President Hamid Karzai, an official has said.

Authorities said on Friday that the blasts happened inside the gated housing complex of Aino Mina on the northern outskirts of the city, that was developed in part by Mahmood Karzai, the president's younger brother.

No one immediately claimed responsibility for the attack.

The bombs were hidden in a motorcycle and a car and were remotely detonated within minutes of each other while parked next to a restaurant area where families were dining, Kandahar government spokesman Javeed Faisal said.

Faisal said that three police officers were among the dead and that an investigation had begun into how the explosives-laden vehicle slipped past the community's heavy security.

Many of the dozens of wounded brought to Mirwais Hospital in Kandahar were in critical condition, Dr Samad Ahmadi said.

In a written statement, Kandahar governor Tooryalai Wesa said: "This pointless attack on innocent Afghans in a peaceful family park is inexcusable."

'Un-Islamic and inhumane'

Aino Mina is home to thousands of Afghan government officials, businessmen and other wealthy citizens who pay around $90,000 for a three-bedroom house on grounds featuring parks, a jogging track and a football field.

Residents have special identification badges, and cars are typically searched before entering the gates.

Mahmood Karzai was one of the main investors in the project, promoted as a triumph of modernity in Kandahar, which is the spiritual birthplace of the Taliban insurgency.

The Karzai clan itself is from Kandahar and another brother of the president, Ahmed Wali Karzai, was a powerful political figure there before being gunned down in 2011 by a bodyguard.

President Karzai's office quickly condemned the attack, noting it was the second such strike in a residential area in two days.

A suicide car bomber hit a US convey in a residential part of eastern Kabul on Thursday, killing 15 people, including nine Afghan bystanders and six Americans.

That attack was claimed by the armed group Hizb-e-Islami.

"Terrorists, by these acts that are un-Islamic and inhumane, are not the followers of any religion," Karzai said in a written statement.