Speaking at the Chatham House international affairs think tank in London, Mr Gargash repeated claims - denied by Qatar - that the country funds extremists.

"This is our message: You cannot be part of a regional organisation dedicated to strengthening mutual security and furthering mutual interest and at the same time undermine that security," he said.

"You cannot be both our friend and a friend of al-Qaeda."

Saudi Arabia and its allies imposed sanctions on Doha on June 5, including closing its only land border, denying Qatar access to their airspace and ordering their citizens back from the emirate.

The four Arab states accuse Qatar of ties to Iran and of funding Islamist extremist groups. Qatar has denied the accusations.

The Gulf crisis is the worst to hit the region since the establishment of the GCC in 1981.

"We've sent a message to Qatar. We've said we are not there to escalate. We are not after regime change. We are after a change of behaviour," Mr Gargash said.

"We need to do that and when we do that, come back to the fold and we can work together," he added.