TIRANA, July 4 -- For six weeks, the demonstrators who gathered nightly outside Albania's government buildings remained remarkably restrained. They carried banners depicting flamingos. They sang. When they blocked a road, they stepped back when asked.

On Thursday, Tirana showed what happens when patience exhausts itself. Albanian riot officers deployed water cannons and pepper spray against a crowd gathered outside the national parliament as Prime Minister Edi Rama's cabinet arrived for a plenary session. Nine police officers sustained injuries from projectiles hurled by demonstrators; a police vehicle had its windows smashed. At least six people had been detained earlier that week after throwing eggs at ministerial vehicles. The confron...