PESHAWAR, Pakistan — Rivers burst their banks during monsoon rains, washing away streets, battering a dam and killing at least 60 people in most severe floods in decades in northwest Pakistan, officials said Thursday. Hundreds of thousands more were stranded as rescue workers struggled to reach far-flung villages.In the Peshawar area, two elderly men clung to a fence post and each other as a raging torrent swept over their heads, footage on Pakistan's Dunya TV showed. It was unclear whether they survived.People were forced to trudge through knee-deep water in some streets in the Swat Valley. A newly constructed part of a dam in the Charsadda district collapsed, while crops were soaked in many areas. At least 10 people died near Peshawar when their homes collapsed.Dozens of people were reported missing, including at least nine Chinese construction workers in the Kohistan area. Some 200 other Chinese workers were trapped amid the downpour, said Mian Iftikhar Hussain, the information minister for Khyber-Pakhtoonkhwa, the province that has been deluged.