U.S. President Barack Obama and Russian President Vladimir Putin have stressed the need to jointly search for ways to help stabilize the situation in Ukraine.

"The sides continued discussing various aspects of the crisis situation in Ukraine. Putin drew attention to the inability and reluctance of the current Kyiv authorities to curb the rampage of ultra-nationalist and radical groups destabilizing the situation and terrorizing civilians, including Russian-speaking population and our compatriots," the Kremlin press service reported.

In this context, they considered the possibility of sending an OSCE monitoring mission to Ukraine.

"According to the Russian president, the activity of such a mission should be extended to all Ukrainian regions," the Kremlin reported.

"In connection with the referendum held in Crimea Putin stressed that its holding was fully consistent with international law and the UN Charter and took into account, in particular, the well-known Kosovo precedent. At the same time, the possibility of free will and self-determination was guaranteed to residents of the peninsula," reads the statement.

The presidents noted that despite the differences in estimates it was necessary to seek ways to help stabilize the situation in Ukraine.