Acting Secretary of Defense Patrick Shanahan has signed off on plans for the U.S. Army Corps of Engineers to reprogram funds for up to $1 billion of infrastructure work on the U.S. southern border in response to a request from the Department of Homeland Security, the Pentagon announced Monday night.

The news comes more than a month after President Donald Trump declared a national emergency regarding security at the border, a move that allowed for the reallocation of DoD funds to border protection.

"These funds will be used to support DHS's request to build 57 miles of 18-foot-high pedestrian fencing, constructing and improving roads, and installing lighting within the Yuma and El Paso Sectors of the border in support of the February 15 national emergency declaration on the southern border of the United States," defense officials said in a statement.

It's not made completely clear whether this fencing is a part of the permanent border wall the president has called for -- a fight over funding for which led to an impasse that triggered a partial government shutdown earlier this year.

The Pentagon's statement added that the Defense Department had the authority to build roads and fences and install lighting to block drug-smuggling corridors in support of federal law enforcement agencies' counter-narcotics activities.

Luke Air Force Base expects to receive two additional F-35A Joint Strike Fighters for its pilot training program with Turkey in coming weeks, even as officials debate complexities surrounding the NATO ally's involvement in the program.

Two jets are expected to arrive at the Arizona base next month, 56th Fighter Wing spokeswoman Maj. Rebecca Heyse said during a phone call Friday.

The first group of Turkish pilots and instructor-pilots have graduated the training program with the 63rd Fighter Squadron as the second and third groups have begun entry-level training at Luke or in San Antonio, Texas, she added.

Heyse could not disclose the number of pilots in the program for operational security and privacy reasons. The first group, which began training in July, will remain at Luke to teach and work with future groups, she said.

Turkish President Recep Tayyip Erdogan announced this weekend that his country -- which hosts Incirlik Air Base, a key Air Force hub -- will continue with its purchase of the Russian-made S-400 surface-to-air missile system.

The deal troubles Defense Department officials, who have said the purchase could result in Turkey's ouster from the F-35 program. Reuters reported last week that the U.S. is considering halting preparations to deliver the F-35 to Turkey in light of its efforts to acquire the Russian system.

"The S-400 is a computer. The F-35 is a computer. You don't hook your computer to your adversary's computer, and that's basically what we would be doing," Katie Wheelbarger, acting assistant secretary of defense for international security affairs, told the news outlet in an interview.

Responding to the Reuters report, Joint Chiefs Chairman Gen. Joseph Dunford said Thursday that he "would have a hard time" justifying future F-35 sales to Turkey.

WASHINGTON — President Donald Trump said Wednesday the last pocket of the Islamic State's land in Syria will be liberated by U.S.-backed forces "by tonight."

Trump has previously announced the defeat of the group, but sleeper cells of fighters have re-emerged. With no signs of fighting Wednesday, however, the long-running battle to retake the militants' last outpost in eastern Syria appeared to have reached its conclusion.

"The caliphate is gone as of tonight," Trump said in a speech at a factory in Lima, Ohio, where military tanks are assembled.

The complete fall of Baghouz would mark the end of the Islamic State group's self-declared caliphate, which at its height stretched across large parts of Syria and Iraq. Controlling territory gave it room to launch attacks around the world.

During his speech, Trump held up two maps of Syria — one covered in red representing territory held by the militant group when he was elected president in November 2016 and the other that had only a speck of red.

"When I took over, it was a mess. They were all over the place — all over Syria and Iraq," said Trump, who has said the U.S. will keep 400 troops in Syria indefinitely.