The American Defence Department says the insurgency in Afghanistan is gaining strength. The level of violence has reached an all-time high, with clashes up fourfold since 2007. In a twice-annual report to the US Congress, the Pentagon said progress had been uneven, with only modest gains against the Taliban insurgency. The Pentagon also reported gains in security, governance, and development in key areas. But it warned the Taliban was exploiting perceptions that NATO countries would soon withdraw combat forces.