(Updates death toll, adds details) SPIN BOLDAK, Afghanistan, July 5 (Reuters) - A suicide bomber in police uniform killed 10 Afghan policemen and wounded 10 others as he sat with them on Thursday at a checkpoint near the southeastern town of Spin Boldak, a local police chief said. Western military officials warn the number of suicide attacks and roadside bombs in Afghanistan is on the rise as Taliban insurgents switch tactics after suffering heavy casualties in conventional clashes with foreign and Afghan troops. "This was a new policeman appointed to our post who blew himself up," one of the surviving officers told Reuters. "There was a huge explosion, the roof of the building collapsed and a big black cloud rose above it." Ten police were killed and 10 others wounded, said Kandahar police Inspector-General Sayed Agha Saqib. The bomber had been sitting among the policemen as they waited for lunch, Border Police General Abdul Raziq Khan said. A Taliban spokesman claimed responsibility for the attack. "It was a suicide bomb. Our Talib wore a police uniform and killed more than 15 policemen," Qari Mohammad Yusuf told Reuters by telephone. Police sealed off the area around the checkpoint near Spin Boldak, a town on the border with Pakistan which sits astride the main road into the southern city of Kandahar and a frequent target of Taliban attacks. In a separate incident, an improvised-explosive device killed one soldier and wounded two more from the NATO-led International Security Assistance Force (ISAF) in eastern Afghanistan, the force said in a statement, but did not give the nationalities of the victims. ISAF has around 38,000 troops based in Afghanistan, while the United States has between 10,000 and 13,000 troops in a separate force.
