Pentagon chief Jim Mattis met Qatar’s Emir Sheikh Tamim bin Hamad Al-Thani Saturday during a visit to the Gulf state which hosts the largest US air base in the Middle East.

The visit to Doha is part of a Mideast tour which has included stops in Saudi Arabia, Egypt and Israel.

Mattis has a scheduled visit to Djibouti on Sunday.

The US Defence Secretary met with Qatar’s emir and was also due to meet with Defence Minister Khaled Al-Attiya during his brief visit, which aimed to improve relations with US President Donald Trump’s administration.

The Gulf-US ties became increasingly frayed during Obama’s presidency, who seemed as too hesitant to intervene in Syria’s war and overly friendly with regional opponent Iran.

Mattis, who commanded troops during the 2003 invasion of Iraq, said on Friday that there was “no doubt” Syria has kept some chemical weapons and warned head of Syrian regime Bashar al-Assad against using them.

Qatar played a major role in the negotiations that led to a recent deal to evacuate thousands of Syrians from besieged towns.

Washington and Qatar have close economic ties, with national carrier Qatar Airways announcing in October the acquisition of up to 100 Boeing aircraft worth $18.6 billion (17.3 billion euros).

The oil-rich Gulf state is home to the Al-Udeid air base which houses around 10,000 US troops.