Toll from Afghan blast rises to 34

The death toll from a suicide car bombing at a military base in eastern Afghanistan has risen to 34, including the bomber.

A suicide car bombing near an eastern Afghanistan military base has left 34 people dead, including the bomber, a government official says.

The bomber detonated an explosives-laden car on Sunday at a military roadblock near Camp Chapman, formerly used by the CIA and currently used by foreign and Afghan troops, in the eastern province of Khost.

The blast took place as people were crossing a security checkpoint to go home to break their fast during Islam's holy month of Ramadan.

"Twenty-seven civilians and six members of the security forces were killed in the bomb blast," said the provincial governor's spokesperson, Mobariz Zadran, on Monday.

The United Nations Assistance Mission in Afghanistan (UNAMA) said three women and 12 children were among those killed.

Another 23 people, including security forces, were wounded in the blast, Zadran said.

The bomber's motive was not immediately clear, he added.

Camp Chapman, located less than four kilometres from the city of Khost, was the target of insurgent attacks in 2009, 2010 and 2012.

Insurgents intensified their countrywide summer offensive in late April, targeting Afghans and foreign troops in what is expected to be the bloodiest fighting season in a decade.

In Kabul, two separate explosions caused by magnetic bombs wounded one civilian in the city's Shahr-e-Naw area on Monday evening, city police spokesman Ebadullah Karimi said.

The United Nations Assistance Mission in Afghanistan (UNAMA), in a report earlier this year, highlighted "anti-government elements" as responsible for 72 per cent of all civilian casualties.