The United States delivered eight Black Hawk helicopters to Jordan on Thursday to help its regional ally defend itself against the threat of Islamic State militants, Jordanian and U.S. officials said.

They said another eight Black Hawks would begin arriving next year under a military aid deal worth about $200 million.

The helicopters are central to a U.S.-funded “Quick Reaction Force” set up by Jordan to counter Islamic State, which controls large swaths of territory in neighboring Iraq and Syria.

In a handover ceremony at Marka military air force base, U.S. Ambassador to Jordan Alice G. Wells said Washington had supplied “millions of rounds of small arms ammunition, hundreds of bombs” and other equipment to Jordan since February last year.

“The United States is committed to standing with Jordan to face the threat posed by Daesh,” she told senior Jordanian army officers, using an Arabic acronym for Islamic State.

“As you employ these aircraft in the fight against Daesh, know that we will be standing right there next to you.”

Jordan is among a few Arab states that have taken part in a U.S.-led air campaign against the hard-line militant group.

In December 2014, a Jordanian pilot was captured by Islamic State after his F-16 crashed in territory it controlled in Syria and later burned alive.

The military aid deliveries address some concerns King Abdullah expressed last year to the administration of President Barack Obama and top U.S. lawmakers about a lack of military funding and responsiveness to one of its key regional allies.

But Jordan’s request for MG-9 Reaper drones was turned down, a U.S. official who requested anonymity said, adding this not “an option right now.

One senior diplomat said ties between the countries had been strained by the king’s enthusiastic endorsement of Russian intervention in Syria, in what some diplomats see as a shift in policy.

U.S. Patriot missiles are stationed in the kingdom, however, and the U.S. Army has hundreds of trainers in the country.

U.S. officials say aid to Jordan, one of the largest recipients of its foreign military financing, is expected to rise to $800 million in 2016 and grow in future years.

Since the start of the Syrian conflict in 2011, Washington has spent millions of dollars to help Amman set up an elaborate surveillance system known as the Border Security Program to stem infiltration by militants from Syria and Iraq.