U.S. Secretary of State Mike Pompeo and his Qatari counterpart Sheikh Mohammed bin Abdulrahman Al Thani on Sunday signed a Memorandum of Understanding (MoU) on the expansion and renovation of Al-Udeid Air Base.

Al-Udeid, which is considered the largest U.S. base in the Middle East, hosts around 10,000 U.S. troops and scores of U.S. combat and supporting aircraft.

In a joint press conference, Pompeo said: “We signed a new MoU on the expansion of our presence at Al-Udeid. It hosts thousands of US military personnel and the CENTCOM forward headquarters. This place is key to American security”.

Al-Udeid is already the largest US military base in the Middle East and is home to the US Air Force Central Command (AFCENT). It houses as many as 11,000 personnel and scores of U.S. combat and supporting aircraft. The base is critical for the projection of US air power in the region.

Qatari Foreign Minister Mohammed bin Abdulrahman Al-Thani, for his part, said that he had discussed the situation in Syria and the fight against terrorism, among a number of other issues of mutual interest, with Pompeo.

“We have held an extended dialogue during the seven meetings of the conference of dialogue between Qatar and the United States and discussed all issues of mutual interest, in particular, the crisis between the Gulf countries, the Middle East peace process, talks on Afghanistan, the situation in Syria, and efforts aimed at combating terrorism,” Al-Thani said.

Last year, Qatari Defense Minister Khalid bin Mohammad Al Attiyah said that the government of Qatar was expanding the Al-Udeid Air Base and sought to make the facility and Washington’s presence there “permanent”.

Pompeo arrived in Doha Sunday from Abu Dhabi, UAE where he had travelled as part of his Middle East tour. The U.S. Secretary of State arrived in Saudi Arabia on Monday.