Russian companies are expected to invest over $50 billion in development of oil and gas fields in Iran, Tass reported quoting Russian presidential aide Yuri Ushakov as saying on Monday.

His Majesty King Abdullah II, on Tuesday received an invitation from the Saudi King Salman Bin Abdul Azizi Al Saud to participate in the Arab Summit scheduled to be held in Dhahran city on April 15.

Turkish President Recep Tayyip Erdogan will host a trilateral summit on Syria on April 4 with the participation of his Iranian and Russian counterparts Hassan Rouhani and Vladimir Putin, the Turkish Presidential Press Office said in a statement on March 31.