At least five soldiers have been killed and dozens of others wounded after a suicide bomber struck a Pakistan army base in a troubled tribal region bordering Afghanistan, officials say.
The bomber attacked the gate of a military camp in Wana, South Waziristan, where Pakistani troops have been battling Taliban and al-Qaeda fighters.
The attack, on Thursday, is the latest in a series of suicide bombings that have put pressure on Pakistan's new government.
"It was a suicide attack. Five troops lost their lives and a dozen others were wounded," a local security official told AFP news agency on condition of anonymity.
"An army truck, some cars and soldiers were stationed at the gate of the camp and the bomber rammed his vehicle into them and blew himself up," the official said.
An army spokesman said officials were investigating a blast which targeted troops in Wana but did not have full details.
The attack came as Dick Cheney, the US vice president, made a surprise visit to Kabul to meet with Hamid Karzai, the Afghan president.
Cheney visit
During the visit Cheney said he expected the new Pakistan government to be a "good and effective" US ally in dealing with fighters along the border.
Pakistan's lawless tribal regions have been wracked by violence since hundreds of Taliban and al-Qaeda fighters fled there after the US-led invasion of Afghanistan in late 2001.
Pervez Musharraf, the Pakistani president, has pushed 90,000 troops into the region but the unrest has spread across the country.
More than 50 suicide attacks took place across the country in 2007 and this year alone there have been at least 20.
Two police officers were killed and six injured after a suicide bomber blew himself up at a police barracks in Pakistan's northern Swat valley on Monday.
In the capital Islamabad on Saturday, a bomb exploded at an Italian restaurant frequented by foreigners, killing a Turkish woman and wounding around 10 other people including four US FBI agents.
Last week 27 people were killed and 200 wounded when two suicide truck bombs exploded in the eastern city of Lahore, one of them targeting a federal investigation agency.
PHOTO CAPTION
Map locates Wana, Pakistan, where Pakistani troops were car bombed.
Al-Jazeera