Sergey Kislyak, Russia's ambassador to the United States. (Cliff Owen/AP) Sergey Kislyak, Russia's ambassador to the United States. (Cliff Owen/AP)

Russian Ambassador to the United States Sergey Kislyak said Sunday that Ukraine needs to change its constitution to better respect regional differences within the nation.

"It’s a country that certainly needs a revision of the constitution that would include a mechanism where the regions would be heard and their views would be taken on board," Kislyak said on ABC's "This Week."

The ambassador also suggested Russia has no intention of withdrawing from Crimea, after host George Stephanopoulos noted that the United States and many European countries are demanding such action after Russia annexed the region.

"Crimea is part of Russian Federation," Kislyak said.

Kilsyak also responded to President Obama's comment last week that Russia is a "regional power" acting out of weakness.

"If you consider Russia a regional power, look at the region that we are in -- it’s from Europe to Asia," the ambassador said. "It’s quite a significant region in the first place. Secondly, I think that those categorizations are very artificial. We are a country with a lot of interests and a lot of things we can contribute throughout the world, but we are certainly not going to overstretch anyway."