KABUL, Dec. 7 -- Pakistan and Afghanistan exchanged heavy fire along their border late on Friday, officials from both countries said, killing at least five people amid heightened tensions following failed peace talks. Afghan Taliban spokesman Zabihullah Mujahid said Pakistani forces launched attacks in Spin Boldak district of Kandahar. A spokesman for Pakistan's prime minister said Afghan forces carried out "unprovoked firing" along Chaman border. "Pakistan remains fully alert and committed to ensuring its territorial integrity," spokesman Mosharraf Zaidi said. P12...