Leaders and heads of delegations of Gulf Cooperation Council (GCC) countries started the 37th session of the GCC Supreme Council in the Bahraini capital Manama yesterday.
Against the backdrop of regional conflict, security and greater integration is said to top the agenda of the two-day summit.
British Prime Minister Theresa May also joined GCC leaders at the summit for talks on trade after Britain's exit from the European Union. Defence ties are also expected to loom high on the agenda as Britain builds a new naval base in Bahrain.
She is the first British premier and the first woman to attend the annual summit of the six Gulf Cooperation Council states.
Up on her arrival late on Monday, Theresa May said: "I will have the opportunity to talk to all six leaders about how we can develop our trade relationship, as well as cooperation on security and defence,"
Ahead of the summit, May held talks with Bahraini officials that also focused on defence ties, the news agency Saudi Gazette reported.
Though trade is high on the agenda, security is the most pressing issue. Bahraini Ambassador to Saudi Arabia Sheikh Hamoud Bin Abdullah Al Khalifa said regional circumstances, growing conspiracies and terror plots give this summit a special importance as it reflects the resolve of the GCC leaders to overcome them and foster cooperation.