Russian President Vladimir Putin expressed "serious concern" on the current Ukraine-Russia situation. Putin called German Chancellor Angela Merkel and requested her to intervene.
"We do not like what's happening, either way we don't like what's happening and hopefully they'll get straight," the US president said, adding, "I know Europe is not they are not thrilled, they're working on it too."
"We're all working on it together," Trump said.
The situation turned into an ugly spat after Russia refused to return the two armoured artillery vessels and a tug boat which was involved in a skirmish with the Russian Navy.
President Petro Poroshenko on Monday pressed for a decree to impose martial law in the country, a move which was backed by Ukrainian lawmakers today.
The martial law will be imposed for the next 30 days in areas vulnerable to attack by Russia. Relations between the two countries nosedived after Russia annexed Crimea in 2014 setting off a cold war-like situation.
NATO chief Jens Stoltenberg called Russia to free Ukrainian ships and sailors while emphasising freedom of navigation for Ukraine in the sea of Azov and Kerch Strait.
"There is no justification for the use of military force against Ukrainian ships and naval personnel," Stoltenberg said.
Ukraine has put its military on high alert after its ships were involved in a clash in the Sea of Azov. Kiev has urged Western nations to consider further sanctions against Moscow.
Russia, on the other hand, has reiterated that Ukraine provoked the situation by entering its territory. Russia reopened the Kerch Strait near Crimea Sea of Azov on Monday even as tensions continued to boil. Russian jet fighters flew over a bridge connecting the Russian mainland with the Crimean Peninsula
Kerch Strait links the Black Sea and the Sea of Azov, dividing Crimea from southern Russia.
Kremlin spokesman Dmitry Peskov accused the Ukrainian vessels of illegally intruding into Russian territorial waters and of ignoring attempts by Russian border guards to contact them.
NATO chief Jens Stoltenberg called Russia to free Ukrainian ships and sailors