KIEV, Dec. 3 (Xinhua) -- The North Atlantic Treaty Organization (NATO) has increased its presence in the Black Sea since Crimea crisis started in 2014, the Ukrainian government-run Ukrinform news agency said on Monday, citing NATO Secretary General Jens Stoltenberg.

"NATO has built up its military presence in the Black Sea region. We also have a greater naval presence. Last year, the number of NATO warships in the Black Sea increased from 80 to 120," Stoltenberg was quoted as saying.

He said that the alliance would also continue to closely monitor the situation in the Sea of Azov.

Last week, Ukrainian President Petro Poroshenko urged NATO to deploy ships in the Sea of Azov amid Ukraine's tensions with Russia in the Kerch Strait near Crimea.

On Nov. 25, three Ukrainian naval ships attempting to sail through the Kerch Strait from the Black Sea to the Sea of Azov were seized by Russian forces for allegedly violating the Russian border.

The Ukrainian Navy said that it had informed Russia in advance of the passage, while Russia said it had received no such report and the ships ignored multiple warnings by the Russian border guards.

The standoff marked the latest incident in relations between Ukraine and Russia, which have been deteriorating since Crimea was incorporated into Russia in March 2014 following a local referendum, which was rejected by Ukraine.