'US sending 3,500 troops to Afghanistan'

The United States has authorized deployment of 3,500 additional troops to war battered Afghanistan.

A US official confirmed to Reuters that Defense Secretary James Mattis has ordered the deployment while the Pentagon said it would not make any announcement until the general speaks out.

The Pentagon chief had reportedly sought to dispatch about 3,900 troops.

Known as "Mad Dog," the general was awaiting the new presidential strategy before making a decision for Afghanistan.

Recently, the US military officially acknowledged that there are some 2,600 more troops in Afghanistan than the 8,400 previously reported. The additional forces would join the 11,000 troops already in the country.

In an executive order issued back in February, US President Donald Trump tasked Mattis with devising an Afghan strategy that was expected to be delivered in mid-July, but the timeline has reportedly been thrown off by the president's demand for revisions.

The United States invaded Afghanistan in October 2001 after the September 11 attacks on New York and Washington, and overthrew the Taliban regime. But US forces have remained bogged down there through the presidencies of George W. Bush, Barack Obama and now Trump.

Taliban militants have warned that they will be stepping up their attacks until the US forces fully withdraw from Afghanistan after more than a decade and half of occupation.