Ukrainian pulls five tramcars with his teeth

A Ukrainian children's doctor pulled five tramcars over a stretch of 14 metres (46 feet) Friday in a stunt in Lviv aimed at drawing attention to Russia's annexation of Crimea in 2014.

The 38-tonne weight was pulled by 34-year-old Oleg Skavysh -- a Ukrainian famous for a series of similar toothy feats.

Pro-Moscow gunmen that Ukraine's Western-backed government suspects were actually Russian soldiers seized the Crimean parliament on February 27 and decided to hold an independence referendum in May.

Russian forces stationed in the Crimean port of Sevastopol seized control of the Black Sea peninsula in the course of the subsequent few weeks.

Crimeans overwhelming voted to join Russia in a March 16 poll that has since only been recognised by a handful of states such as Syria and North Korea.

Russian President Vladimir Putin formally annexed Crimea on March 18.

The United Nations' General Assembly voted by a near-unanimous margin to proclaim the annexation as illegal on March 27 of that year.

Ukrainian President Petro Poroshenko vowed once again on Friday to eventually force Russia to return the strategic region of around two million people that has been a popular resort destination since Soviet times.

He also order his government to develop a detailed plan of how Ukraine could defend its case in international courts.

"Crimea was, is and will remain an integral part of the Ukrainian state, and the thieving nation will have to return what it stole," Poroshenko said in a statement.

"Russia has substantially boosted its military presence in the region... that is posing a threat -- including a nuclear one -- not just to Ukraine, but to all the countries of the Black Sea region," the Ukrainian leader added.

Russia has stationed new warplanes and deployed additional troops to back up its existing naval base in Crimea.