Ukraine's military said on Monday it had launched three-day naval exercises with US-led NATO forces in the Black Sea aimed at guaranteeing its security "in a crisis region".

A top defence spokesman said the annual Sea Breeze drills involve seven Ukrainian ships and five from NATO countries.

"The purpose of these exercises is to ensure that we are able to establish and hold a secure shipping zone in a crisis region," Andriy Lysenko told reporters.

The drills are being conducted off Ukraine's southwestern coast due to Russia's March annexation of Crimea and effective control over the Sea of Azov that runs along the southeast of Ukraine.

Previous Sea Breeze exercises staged around the Russian-operated Crimea port of Sevastopol had provoked repeated protests from Moscow.

Ukraine has organised an annual series of drills with NATO countries since first establishing partnership relations with the Western alliance in 1997.

The ex-Soviet country initially announced plans to join the military bloc in 2002 before reversing its decision under Russian pressure.

A crisis in relations with Moscow sparked by the five-month pro-Kremlin uprising in eastern Ukraine saw Kiev reaffirm last month that it planned to join the bloc to assure its protection from Russia.

Ukraine will also conduct two weeks of annual Rapid Trident ground manuevers with US and NATO forces in the west of the country starting on September 13.