A senior counter-terrorism adviser to Qatar's foreign minister has hit out at the diplomatic squeeze on Doha by several Gulf states, calling it a "policy of domination and control."

US President Donald Trump has accused Qatar's leadership of bankrolling extremists and demanded a halt to that funding, drawing praise Saturday from Saudi Arabia and its allies.

Their approval came as Washington joined intensifying international efforts to heal the rift between the key Western Gulf allies, which has escalated into the region's worst diplomatic crisis in years.

Efforts to resolve a diplomatic dispute pitting Saudi Arabia and its allies against Qatar intensified Thursday, after Washington offered to mediate the biggest crisis to grip the Gulf in years. 

U.S. President Donald Trump threw his weight behind efforts to isolate Qatar on Tuesday, backing Saudi Arabia and its allies after they cut ties with Doha over claims it supports extremism.

In a surprise move against a key U.S. ally, Trump suggested Qatar -- home to the largest American airbase in the Middle East -- was funding extremism as he tacitly backed the diplomatic blockade of the emirate.

Gulf sanctions against Qatar could damage reconstruction in the Hamas-run Gaza Strip, where it has provided large financial backing, the head of a major humanitarian charity warned Tuesday.

A Saudi-led diplomatic and economic blockade against Qatar may threaten food imports but the tiny emirate still has a lifeline through its gas and oil exports, experts said Tuesday.

Saudi Arabia, the UAE, Bahrain, Egypt and Yemen on Monday cut ties with Qatar, a small Gulf state which burst onto the diplomatic scene thanks to its rich energy resources.

Qatar Airways said on Monday it had suspended all flights to Saudi Arabia as a major diplomatic crisis escalated in the Gulf region.

Saudi Arabia, Bahrain and the United Arab Emirates severed ties with Gulf neighbor Qatar on Monday over accusations it supports extremism, with Egypt and Yemen following suit. 

Iranian Foreign Minister Mohammad Javad Zarif held talks Wednesday with the emir of Qatar, on his first visit to the Gulf state since July 2015.