Demonstrations against the results of the contested Ukrainian presidential runoff election spilled from the streets of Kiev onto the sidewalks of Manhattan, as well as other major American cities yesterday.

Russian-backed Viktor Yanukovich was declared president on Monday, but Ukrainian and international officials have alleged there was systemic voter fraud in an election that the opposition candidate, Viktor Yushchenko, was expected to win.

Supporters of Mr. Yushchenko, wrapped in the blue-and-yellow Ukrainian flag and wearing his party color of orange, stood to protest in front of the Russian mission to the United Nations on 67th Street yesterday.

A Ukrainian-American protester, Ulana Kekish, who said she was a close family friend of Mr. Yushchenko, said his campaign was bolstered by the widespread show of support from Ukrainians who are living abroad. She relayed the chants of “Yushchenko!” to his campaign officials in Kiev by holding her cell phone to the crowd.

“I let them listen, and they were completely ecstatic,” Ms. Kekish said. “They put me on speaker phone.”

Ms. Kekish added, “You’ve never seen something so uplifting. People will not go back to being told who their leader is,” she said.

The several hundred protesters, according to police estimates, marched from the Ukrainian Consulate on 49th Street to the Russian mission to the United Nations on 67th street and then south to the United Nations itself.

A Russian official in charge of security at the mission said he had not expected the demonstrators, who booed and hissed as people emerged from the building on the Upper East Side.

Officials from Ukrainian civic groups around the country began planning protests after the disputed results were announced on Monday, said an organizer of one of the groups, George Pylyp.

Similar protests took place yesterday in Chicago and San Francisco. Ukrainians from Philadelphia hired two buses to take them to the city, where people converged from the tri-state area.

The groups plan a major march today at noon in Washington, D.C., from the Ukrainian Embassy to Capitol Hill.

“We need this victory,” said one of the protesters, Tetiana Yaroshenko, a Fulbright scholar from Kiev studying at Yale University. “It’s a terrible situation but we need democracy.”