KABUL, Afghanistan  Airstrikes on Taliban insurgents have risen sharply here over the past four months, the latest piece in what appears to be a coordinated effort by American commanders to bleed the insurgency and pressure its leaders to negotiate an end to the war.

American pilots pounded the Taliban with 2,100 bombs or missiles from June through September, with 700 in September alone, Air Force officers here said Thursday. That is an increase of nearly 50 percent over the same period last year, the records show.

The stepped-up air campaign is part of what appears to be an intensifying American effort, orchestrated by Gen. David H. Petraeus, to break the military stalemate here as pressure intensifies at home to bring the nine-year-old war to an end. In recent weeks, General Petraeus has increased raids by Special Forces units and launched large operations to clear territory of Taliban militants.

And it seems increasingly clear that he is partly using the attacks to expand a parallel path to the end of the war: an American-led diplomatic initiative, very much in its infancy but ultimately aimed at persuading the Taliban  or large parts of the movement  to make peace with the Afghan government.