Russia’s Sputnik V vaccine against the coronavirus will have to wait longer for a decision on emergency use authorization by the World Health Organization.

A W.H.O. official said on Wednesday that the organization was forced to delay the assessment process for the vaccine because of difficulties created by Russia’s invasion of Ukraine.

“We were supposed to go do inspections in Russia on the 7th of March, and these inspections were postponed for a later date,” said Dr. Mariângela Simão, an assistant director general of the W.H.O., at a news conference in Geneva. “The assessment, along with inspections, have been affected because of the situation.”

Dr. Simão said that obstacles to booking flights into Russia and using credit cards while there were among the many issues confronting the agency’s inspectors. After Russian forces invaded Ukraine on Feb. 24, most Western countries closed their airspace to Russian aircraft, and Mastercard and Visa suspended operations in Russia.

Dr. Simão said a new timetable would be drawn up as soon as possible.

The two-dose Sputnik V was developed by the Gamaleya Research Institute, part of Russia’s Ministry of Health. Russia began distributing the vaccine in the fall of 2020, and regulators in more than 70 countries have approved it for use, according to the Russian Direct Investment Fund, which backed the vaccine’s development.

But Sputnik V has not yet been approved by the European Union’s main drug regulator or the World Health Organization. Russians and other travelers who have received the vaccine have had a difficult time entering the European Union or the United States.

Though President Vladimir V. Putin of Russia has called Sputnik a medical breakthrough, the country repeatedly failed to follow international procedure and provide all the data foreign regulators need to assess safety of a vaccine that was rushed through large-scale clinical trials to speed its release in the fall of 2020. An E.U. health official accused Russia’s government last fall of repeatedly delaying inspections of Russian facilities. But Russian officials insist that the delays in the approval process have been political.

Russia cleared a hurdle in February 2021 with the publication in the British medical journal The Lancet of late-stage trial results showing that Sputnik V vaccine was safe and highly effective. Even then, many countries, including Brazil and South Africa, have rejected using it. Ukraine also does not recognize Russia’s Sputnik V vaccine.

The United Nations-backed Covax program that distributes vaccines globally to low- and moderate-income nations cannot use vaccines that are not approved by the W.H.O.

About half of Russian adults have been fully vaccinated, according to the Our World in Data project at the University of Oxford.