KIEV, Ukraine — Ukraine’s besieged interim government raced to head off violence that might set off a Russian invasion of its eastern provinces on Sunday, recruiting wealthy eastern businessmen to become provincial governors in an effort to dampen secessionist sentiment there.

As complete Russian control of Ukraine’s Crimean Peninsula became a reality on Sunday, with Western officials reporting that thousands more Russian troops were flowing into the region, worries mounted in Kiev that the east could be next to fall.

In Kharkiv, the eastern city that is the country’s second-largest, a sprawling pro-Russian protest camp occupied the central square, and Russian flags were on display. Many said they would even prefer that Russian troops invade the city, just 20 miles from the border, instead of submitting to Kiev’s rule.

“I would welcome them with flowers,” said Aleksandr Sorokin, 55, a pensioner walking by a phalanx of riot police officers guarding the administration building in Kharkiv. “We do not want to spill blood, but we are willing to do so.”