BUENOS AIRES, Dec. 2 (Xinhua) -- Russian President Vladimir Putin said on Saturday on the sidelines of a G20 summit in Buenos Aires there had been no discussion with Ukraine about the possible release of the Ukrainian sailors who were seized along with their ships by Russia last month.

Russia is resisting international calls to release three Ukrainian naval ships that its border patrols fired upon and seized in the strait near Russian-annexed Crimea last weekend.

Putin said he would not introduce tit-for-tat restrictions on the entry of Ukrainians into Russia after Kiev imposed a ban on Russian males aged 16 to 60 from entering its territory.

Moscow accused the 24 sailors of illegally crossing the Russian border.

After U.S. President Donald Trump canceled a planned meeting with Putin at the G20 summit, citing the military tensions with Ukraine, the Russian leader said there were no pre-conditions for future bilateral talks.

“It is regrettable that we can't succeed in holding a full-scale meeting, which is long due,” Putin said, adding that issues of strategic stability would be of paramount importance.

U.S. President Donald Trump and German Chancellor Angela Merkel on Saturday exchanged views on the sidelines of the Group of 20 (G20) summit in Buenos Aires.

The two leaders discussed the ongoing situation of confrontation between Russia and Ukraine, and Russia's violation of the Intermediate-Range Nuclear Forces (INF) Treaty and explored how to strengthen the NATO alliance further as well as how to improve European energy security, according to a statement released by the White House.

On Saturday, the Kremlin made a statement that Russian President Vladimir Putin and U.S. leader Donald Trump are unlikely to hold talks in the near future after the latter canceled their scheduled meeting in Argentina.