MOSCOW — As Russian-backed rebels entrenched themselves in a newly captured, strategically located town in southeast Ukraine on Friday, President Vladimir V. Putin bluntly strengthened Moscow’s hard-line position that the government in Kiev must be compelled to negotiate regional autonomy.

Abandoning his more frequent conciliatory stance, Mr. Putin issued a rare, open, congratulatory message to the insurgents. They had “achieved a major success in intercepting Kiev’s military operation,” he said on his website.

Behind the message, and the wider military operation, analysts saw several Kremlin goals. Most important, they said, is that Mr. Putin wants to force terms, first laid down in March, built around political changes in Ukraine that would weaken central government authority and ensure that the country cannot escape Moscow’s orbit — and certainly never join NATO or other important Western alliances. Second, but perhaps more urgent, Russia wanted to take the pressure off the increasingly beleaguered rebel forces in Luhansk and Donetsk, which were at risk of capture by government forces, hence robbing Moscow of important leverage.

Third, there was the possibility that Russia was trying to establish a land route to Crimea, the southern Ukrainian peninsula seized in March. Analysts noted, though, that such a possibility would mean a notable shift in policy — never easy to assess given the opaque statements from the Kremlin.