ISTANBUL (AP) — U.S. Secretary of State Rex Tillerson embarks on his first shuttle diplomacy mission this week, hopping between Gulf Arab nations in a bid to resolve a crisis over Qatar that has embroiled the region.

The State Department said Tillerson would shuttle between Kuwait, Qatar and Saudi Arabia from Monday to Thursday seeking to ease long-simmering tensions that boiled over last month.

In early June, Saudi Arabia, Bahrain, the United Arab Emirates and Egypt broke ties with and imposed a blockade on Qatar over its alleged support for extremists. Kuwait has been leading a mediation effort but Qatar has rejected the four nations' demands to end the deadlock.

Tillerson will travel from Istanbul to Kuwait City on Monday for talks with Kuwait's emir. He will then visit Qatar and Saudi Arabia, using Kuwait as a base, although specifics of those meetings were not immediately announced.