MOSCOW, September 03. /ITAR-TASS/. Four NATO warships will enter the Black Sea before September 7: US Navy’s destroyer USS Ross, the Commandant Birot ship of the naval forces of France, Canadian Navy’s HMCS Toronto frigate and Spanish frigate Almirante Juan de Borbon, a military-diplomatic source told ITAR-TASS on Wednesday.

USS Ross and Commandant Birot will pass the Black Sea straits on Wednesday, September, 3, the source added.

“The Spanish and Canadian frigates are to enter the waters of the Black Sea on September 6,” he said.

According to the source, the French intelligence ship Dupuy de Lome will leave the Black Sea area on September 5.

According to the Montreux Convention of 1936, warships of non-Black Sea states can stay in the Black Sea for no more than 21 days.