An explosion tore through a densely populated neighborhood in Damascus on Friday, killing 25 people and wounding dozens more in the second attack in the Syrian capital in two weeks, Syrian television and other state media reported. Government media said the attack was carried out by a suicide bomber at a busy intersection, and television broadcast images of a wrecked police bus, asphalt smeared with blood and glass and the shattered windshields of other vehicles. It said the blast was “a powerful explosion” in the neighborhood of Midan, which has proven restive, and it said both civilians and personnel with the security forces were wounded and killed.