Bombing in Afghanistan kills six

Six people were killed in a bomb attack on a base operated by Polish and Afghan forces in the eastern Afghan province of Ghazni on Wednesday, local officials and a Reuters witness said.

Another 20 people -- including at least nine soldiers -- died in a spate of bombings elsewhere in the country. Violence has intensified across Afghanistan this week as Taliban insurgents seek to increase pressure on NATO contingents preparing to withdraw by the end of 2014.

The Taliban, which claimed responsibility for the base attack, in which at least 34 others were wounded, said a suicide bomber detonated himself near a truck loaded with explosives.

"The bombing wiped out the security posts and the first checkpoint while other fighters, armed with heavy and light weapons, managed to get inside and are firing at intended targets," Taliban spokesman Zabihullah Mujahid said in an email.

Gunshots continued to ring into the night following the attack at around 4 p.m. (1130 GMT), Ghazni's deputy governor said. A Reuters witness saw a column of black smoke rising from the base in the provincial capital. At least four civilians and two police officers were killed in the fighting, according to local health official Baz Mohammad Hemat.

Eight children and two women were among the 34 wounded. Elsewhere in Afghanistan, two attacks in Helmand province on Wednesday killed three soldiers and 10 Afghan civilians and wounded more than 20 other people, police and provincial officials said.

One of the attacks took place in Helmand's provincial capital, Lashkar Gah, where a suicide bomber blew himself up near a foreign troop convoy but without killing or wounding any of the soldiers targeted, a spokeswoman for the NATO-led force said.

In the second attack, on the outpost of Nad Ali in Helmand, a suicide bomber in a car killed three soldiers, officials said. Helmand has been the scene of some of the fiercest fighting between NATO-led forces and the insurgents since the overthrow of the Taliban in 2001.

On Tuesday, in the western province of Farah, Taliban insurgents torched 40 trucks that supply NATO-led forces with fuel and killed six Afghan drivers, said the provincial governor's spokesman, Abdul Rahman Zhwanday.

And in Kabul, a suicide bomber targeted a government ministry, killing himself and one other person, according to security sources in the capital.

Al Jazeera and wire services