US Defense Secretary Mark Esper called on the Gulf Cooperation Council (GCC) countries to resolve their differences, which he said have dragged on, to focus on confronting Iran, the region's biggest challenge.

"Our message to the GCC countries is that they need to resolve their differences quickly," Esber said in a speech at the Royal United Services Institute in London on Friday.

"This is the biggest challenge for us and the countries of the region, I think.

Esber's comments come amid renewed diplomatic contacts over the Gulf crisis recently. The US ambassador to Kuwait, Lawrence Silverman, said a few days ago that the Gulf crisis will be present among the files to be discussed by the Emir of Kuwait, Sheikh Sabah Al-Ahmad Al-Sabah, during his scheduled meeting with US President Donald Trump in Washington on September 12.

Kuwaiti Speaker Marzouq Al-Ghanim conveyed a message from the Emir of Kuwait to the Emir of Qatar, Sheikh Tamim bin Hamad Al-Thani, on Thursday (August 29th).

Al-Ghanim's message followed a verbal message from Saudi Arabia's State Minister Prince Turki bin Mohammed bin Fahd al-Saud from Saudi King Salman bin Abdul Aziz and Crown Prince Mohammed bin Salman to the Emir of Kuwait.