MOSCOW — President Vladimir V. Putin of Russia called on Ukraine on Sunday to begin talks on “the statehood” of that country’s rebellious southeast, a vague and provocative turn of phrase he used while demanding that the Ukrainian government negotiate directly with pro-Russian separatists.

Western governments have accused Russia of backing the separatists with arms and fighters and of sending Russian troops to lead a counteroffensive in Ukraine over the past week that threatened Mariupol, an important port city, and left thousands of government troops encircled.

“We must immediately begin substantive, meaningful negotiations, not on technical questions, but about the political organization of society and the statehood of Ukraine’s southeast for the unconditional securing of the legal interests of the people who live there,” Mr. Putin said.

Dmitri S. Peskov, Mr. Putin’s spokesman, said that Mr. Putin was not calling for independence for eastern Ukraine. Rather, he said, the Russian leader was seeking inclusive negotiations that would provide greater autonomy for the southeast as it remained a part of the country.