Sheikh Mohammed and General Koji Yamazaki, chief of staff of Japan's ground forces, discussed cooperation "in the defence and military sectors", the United Arab Emirates news agency WAM reported.

The tanker Kokuka Courageous was carrying highly flammable methanol through the Gulf of Oman on Thursday when it was set ablaze along with the Norwegian-operated Front Altair -- the second assault in a month on tankers in the strategic shipping lane.

The United States and its ally Saudi Arabia have accused Iran of being behind the attacks, charges denied by Tehran.

The latest attacks took place as Japanese Prime Minister Shinzo Abe was holding talks in Tehran.