WASHINGTON (Reuters) - President Barack Obama's top security adviser has told U.S. military commanders there are no plans to send more troops to Afghanistan for now and that the focus instead will be on economic development and reconstruction, The Washington Post reported on Tuesday.

National Security Adviser James Jones delivered that message last week in Afghanistan, where Marine Brigadier General Lawrence Nicholson hinted he could use more "thousands more" troops, the newspaper said.

Jones' message seemed designed to cap expectations that more troops might be coming, although the Obama administration has not ruled out additional deployments in the future, the Post said.

"This will not be won by the military alone," Jones told the Post during his trip. "We tried that for six years."

"The piece of the strategy that has to work in the next year is economic development. If that is not done right, there are not enough troops in the world to succeed."

An extra 17,000 troops Obama deployed to fight a growing Taliban-led insurgency in southern and western Afghanistan were expected to be on the ground by mid-July. Another 4,000 troops being deployed to train Afghan security forces are due to arrive by August.

The forces are part of a build-up that could expand the U.S. military presence in Afghanistan to 68,000 troops by the end of this year, more than double the 32,000 at the end of 2008.

The Post said Jones made it clear during his visit to Afghanistan that it was a new era and Obama will not automatically give military commanders whatever force levels they request, a departure from the practice of the Bush administration in the Iraq war.

(Editing by John O'Callaghan)