The Republican-led House is pushing ahead with a $611 billion defence policy bill that prohibits closing the prison at Guantanamo Bay, Cuba, forbids the Pentagon from trimming the number of military bases and awards US troops their largest pay raise in six years.

Lawmakers are scheduled to vote Friday on the legislation, which authorises military spending for the fiscal year that started Oct 1.

The defence bill includes an agreement that prevents the Defence Department from forcing thousands of California National Guard troops to repay enlistment bonuses and benefits they received a decade after they signed up to serve in Iraq and Afghanistan.

During his 2008 bid for president, Barack Obama pledged to close the detention facility at Guantanamo, which he called a recruiting tool for extremist groups.

But Republicans and a number of Democrats repeatedly thwarted his goal over the ensuing years, arguing the prison was badly needed for housing suspected terrorists.

The ban on closing the prison also includes a prohibition on moving Guantanamo detainees to secure facilities in the US.

President-elect Donald Trump has not only pledged to keep Guantanamo open, he said during the campaign that he wants to “load it up with some bad dudes.”

The defence legislation also authorises a 2.1 per cent pay raise for the troops a half-percentage point higher than the Pentagon requested in its budget presentation. The Republican chairman of the Armed Services Committee, Sen. John McCain of Arizona, said it's the largest military pay increase since 2010.

The White House Office of Management and Budget objected to the larger raise, telling lawmakers earlier this year that the lower amount would save $336 million this fiscal year and $2.2bn through 2021.

A bigger raise, it said, would upset the needed balance between competitive pay and acquiring cutting-edge equipment and training.

The defence bill blocks the Pentagon's planned reductions in the number of active-duty troops by prohibiting the Army from falling below 476,000 active-duty soldiers 16,000 more than Obama's defence budget had proposed. The bill also adds 7,000 service members to the Air Force and Marine Corps.

House and Senate negotiators who crafted the defence bill dropped a House plan to shift $18bn from the emergency wartime spending account to pay for additional weapons and combat gear the Pentagon didn't request.

The negotiators elected instead to boost the wartime account, which isn't constrained by mandatory budget limits, by $3.2bn to help halt a decline in the military's ability to respond to global threats.

The decision may have been motivated by Trump's assurances that he would increase defence spending dramatically, allowing the armed forces to add tens of thousands more troops and acquire new weapons.

Lawmakers also inserted into the defence bill the $5.8bn in additional war-related funding Obama requested last month.

The so-called supplemental includes $2.5bn to maintain elevated US troop levels of 8,400 in Afghanistan as announced over the summer.

About $383m would pay for air strikes against Islamic State fighters.

Lawmakers avoided wading more deeply into social policy issues by stripping two contentious provisions from the bill.

One, opposed by Democrats, would have allowed federal contractors to discriminate against workers on the basis of sexual or gender orientation.

Another, opposed by Republicans, would have required for the first time in US history that young women sign up for a potential military draft.

Key provisions in the defence policy bill

• Guantanamo: The bill prohibits Obama from closing the detention facility at Guantanamo Bay, Cuba. Detainees also are barred from being moved to secure facilities in the US.

• Stops troop drawdown: The Pentagon is blocked from making planned reductions in the number of active-duty troops. The Army is prohibited from falling below 476,000 soldiers. The bill also adds 7,000 service members to the Air Force and Marine Corps.

• Pay raise: The troops are awarded a 2.1pc pay raise. That's a half-percentage point higher than the Pentagon requested.

• No base closures: The bill rejects a Pentagon plan to begin a new round of military base closures.

• Guard bonuses: The bill includes an agreement that prevents thousands of California National Guard troops from being forced to repay enlistment bonuses and benefits.

• Wartime operations: The legislation includes the $5.8b in additional war-related funding Obama asked for last month. The extra money includes $2.5b to maintain elevated US troop levels of 8,400 in Afghanistan. About $383m would pay for air strikes against Islamic State fighters.