Afghan and NATO forces clashed with Taliban militants in a dangerous southern region overnight, leaving 33 suspected insurgents dead, the provincial governor said Tuesday. The joint forces carried out the nighttime operation in the Zhari district of Kandahar, said provincial governor Asadullah Khalid. Four other suspected militants were arrested, including three wounded in the battle. There were no casualties among Afghan or NATO forces, he said. Zhari was the site of one of NATO's largest-ever operations last fall and remains a volatile region. Seven Afghan police died in a roadside bomb explosion in Zhari on Monday, the Associated Press reported.