MOSCOW — Russian President Vladimir Putin and German Chancellor Angela Merkel discussed how Moscow and the West can help "restore stability" in Ukraine during a telephone call on Monday, the Kremlin said.

Putin told Merkel that Ukraine must enact constitutional reforms to ensure that the interests of all its regions are respected, and called for measures to end what he called a "blockade" of Moldova's breakaway Transdniestria region, his office said.

Russia has seized the Crimean peninsula from Ukraine and warned it could send its military into eastern Ukraine to protect Russian-speakers there, but has also engaged in diplomacy that it says is aimed at decreasing tension.

Putin and Merkel discussed "opportunities for international support for the restoration of stability" in Ukraine, the Kremlin statement said. It gave no details, but Russia has indicated it wants Western states to press the Kiev government to grant broad autonomy to Ukraine's regions.

Western officials have expressed concern that Putin may have set his sights on pro-Russian Transdniestria, on Ukraine's western border, following the annexation of Crimea.

Putin's comments appeared aimed at turning the tables, blaming others for tension over Transdniestria and saying it could not be ignored.

"The Russian leader spoke of the need to take effective measures aimed at removing the de facto external blockade of this region and at searching for a fair and comprehensive solution to the Transdniestria issue," the Kremlin statement said.

Transdniestria, with a population of half a million, has run its own affairs since 1992 after fighting a brief war against the Moldovan government over fears that it might join Romania after the collapse of the Soviet Union. Russia has a permanent garrison of peacekeepers there.