SIMFEROPOL, Crimea — With one exit poll showing that 93 percent of Crimeans voted to join Russia, and street celebrations under way, the peninsula’s pro-Kremlin prime minister and a Russian nationalist politician pledged quick integration.

The bravado and declarations of speedy Russian annexation of Ukrainian territory came after a deeply flawed vote held under the intimidating presence of at least 21,000 Russian soldiers, who invaded in late February.