A suicide bomber rammed an explosives-laden vehicle into a military checkpoint in Pakistan's northwest on Saturday, killing at least 20 people, officials said. The checkpoint is near the Orakzai tribal region, Associated Press reported. The explosion wrecked a building housing troops and police next to the checkpoint, said Farid Khan, a senior police official in the nearby town of Hangu. At least 18 members of the security forces as well as two civilians died, Khan said. More than a dozen other people were wounded, including the local police chief, other officials said.