BEIRUT — Clashes between Syrian insurgents and loyalist troops in Damascus raged for a second day on Thursday and spread to the suburbs and other areas, activist groups reported. Fighting also erupted in the large Palestinian refugee neighborhood of Yarmouk on the capital’s southern outskirts, which had already been drawn into the civil war at least twice in the past few months.

The expanded mayhem, described as some of the worst fighting to afflict Damascus in months, offered further indication that any hope for a diplomatic resolution to the nearly 2-year-old conflict has all but evaporated. Those hopes were resurrected last week when the leader of Syria’s largest political opposition group suggested holding talks with President Bashar Assad’s government.