KIEV, Dec. 5 (Xinhua) -- The Ukrainian Foreign Ministry said on Wednesday it has appealed to the Budapest Memorandum guarantor countries the United States, Britain and Russia, for urgent consultations over the tensions in the Kerch Strait.

"Ukraine is constantly considering the Budapest Memorandum as an important international instrument for ensuring Ukraine's security," the ministry said in a statement on its website.

Under the Budapest memorandum signed in December 1994, Ukraine got security guarantees from Washington, London and Moscow in exchange for Kiev to sign the Non-Proliferation Treaty and surrender what was then the world's third-largest nuclear arsenal.

On Nov. 25, three Ukrainian naval ships and more than 20 sailors 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 called the incident an "act of aggression," saying it had informed Moscow in advance of the passage. Meanwhile, Russia said it had received no such report and the ships ignored multiple warnings by the Russian border guards.