President Donald Trump is pushing a $500 billion military deal to train troops in Afghanistan to be put on hold after lawmakers refused to approve the deal amid concerns over the U.S. government’s readiness.

The Pentagon has been pushing for the deal since January, when Defense Secretary Jim Mattis, then chairman of the Joint Chiefs of Staff, told Congress he would not sign off on the deal.

The new U.N. mission to the region is meant to increase the country’s capabilities in an effort to confront the Taliban.

The $500bn would help Afghanistan get the equipment and expertise it needs to be able to respond to an eventual withdrawal of U.A.E. troops by 2020.

But the Trump administration has struggled to overcome opposition from lawmakers who have said the military’s presence is needed to keep the peace in Afghanistan.

The Trump White House on Friday released a draft of a plan to spend $400bn in the coming decade on new equipment, training and other military support.

The White House said the money would come from the $1.6 trillion Overseas Contingency Operations Fund and be spent “in a manner consistent with the goals of the United Nations.”

The draft, obtained by POLITICO, said the funds would be used to train about 5,500 Afghan forces, according to a White House official.

A Pentagon spokesman did not immediately respond to a request for comment on the draft.

But Sen. Joe Manchin, D-W.

Va., a member of the Senate Armed Services Committee, said in a statement Friday that he was disappointed the administration “has decided to halt the funding.”

Manchin said the Trump plan “will make it harder for the United States to win the hearts and minds of Afghans, especially when we have to continue to train, equip, and support our Afghan partners who are already fighting a losing battle.”

The Trump plan, Manchin continued, would “result in an Afghan-led Afghan security force that is not only incapable of holding the line against Taliban insurgents, but which will instead have to use American military power to defend itself.”

Mattis in January said the U:s.

military was ready to go to war in the Middle East “with the full support of the American people” and that it was a “top priority” to get the $500b.

The plan is meant as a way to ensure that Afghan forces are “ready and able to take the fight to the Taliban once and for all.”

Mattis and Gen. John Nicholson, the White House defense chief, said they wanted the military to be ready to take over in case Afghanistan decided to pull its forces out.

They said the $50bn in new funding was needed to increase Afghan security forces and provide the military with a “boots on the ground” to train the Afghan National Security Forces, the elite special forces who are battling the Taliban in the country.

“The goal is to create a new military presence that is a fully integrated part of the Afghan national security force,” Mattis said.

Trump’s move follows a bipartisan effort to cut $400 billion from the Overseas Security Cooperation Agency budget and set aside $50billion for the new mission.

Senate Armed Service Committee Chairman John McCain, R-Ariz., has said he will not support a new U,S.

military mission in Afghanistan, which is slated to expire in 2020.

McCain said Friday he would work with the administration to find another way to support Afghan forces.

“I’m not going to sit idly by and let a new mission in the region go to waste,” McCain said in an interview with Fox News.

“This has been an important investment in our future.”