Defense Secretary Jim Mattis on Thursday said he has signed the order to deploy additional forces to Afghanistan as part of President Donald Trump’s new South Asia policy.

“I have signed orders, but it is not complete,” Mattis told reporters at the Pentagon. Mattis said some aspects of the policy are still being negotiated, and would not comment on the additional troop numbers, nor when they would arrive.

More information will be given in the next few weeks as he prepares to brief lawmakers on Sept. 6, the secretary said.

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“By and large this is to enable the Afghan forces to fight more effectively,” Mattis said. “It’s more advisers, more enablers,” such as “fire support” teams, Mattis went on to say, but declined to specify further. Said units have not yet arrived in Afghanistan, Mattis clarified.

The SecDef’s comments come hours after The Washington Post reportedthat U.S. Marine Corps artillery detachments along with members of the the Army’s 82nd Airborne Division and 25th Infantry Division are expected to deploy.

The increase could include additional strike rotations from B-52 Stratofortress bombers, F-16 Fighting Falcons fighter jets, and A-10 close-air support mission aircraft, the Post said, citing unnamed sources.

Meanwhile, the U.S. commander in Afghanistan last week said that “additional capabilities” were already arriving in the military buildup announced earlier this month by Trump. However, Army Gen. John Nicholson, commander of U.S. Forces-Afghanistan and the NATO Resolute Support Mission, was careful not to say whether the new “capabilities” included more troops.

On Wednesday, the Pentagon clarified it already has more troops in Afghanistan than previously reported.

The long-standing official Force Management Level has been 8,448 — but Marine Lt. Gen. Frank McKenzie, director of the Pentagon’s Joint Staff, said for the first time that the actual number in Afghanistan is about 11,000.

“That’s the total forces that are in Afghanistan today. Should that number change significantly, then we will come back in here to tell you,” he told reporters during a briefing.

The latest Afghanistan news from the Pentagon comes as the U.S. Army is preparing to send two brigades from the 3rd Infantry Division to Afghanistan this fall as part of regularly scheduled rotations to the theater.

The Army did not release the number of 3rd ID soldiers involved in the upcoming fall deployment, and neither the Army nor the Defense Department could provide the number when contacted by Military.com.

The 3rd ID units will replace the 16th Combat Aviation Brigade, 7th Infantry Division, and the 1st Sustainment Brigade, 1st Armored Division, to support Operation Freedom’s Sentinel, according to a release.

— Reporters Richard Sisk and Matthew Cox contributed to this report.

— Oriana Pawlyk can be reached at oriana.pawlyk@military.com. Follow her on Twitter at @Oriana0214.