Threats to a string of European Olympic offices are reviving a question that has haunted preparations for the Winter Games next month: Is it safe to go to Sochi?

European Olympic authorities, whose countries have faced terrorist threats and attacks in the past, largely shrugged off the new menacing messages as a hoax, a marginal phenomenon that security experts say is common ahead of big events.

Some members of the U.S. Congress aren’t so sure. They say Russia isn’t doing enough to assure that athletes will be protected at the Feb. 7-23 games, being staged not far from the scene of an Islamic insurgency that Russia’s huge security apparatus has struggled for two decades to quell.

Suicide bombings last month a few hundred miles away from Sochi have increased concerns, and an Islamic warlord has urged his followers to attack the Olympics, Russian President Vladimir Putin’s pet project.

The threats reported Wednesday appeared to be less genuine. They were first revealed by Hungarian sports officials, who announced they had received an email in Russian and English threatening Hungarian athletes with terrorist attacks.

The International Olympic Committee insisted it takes credible threats seriously, but “in this case it seems like the email sent to the Hungarian Olympic Committee contains no threat and appears to be a random message from a member of the public.”

Several other European countries, including Britain, Germany, Italy and Austria, had received similar messages but hadn’t publicly reported them.

Wolfgang Eichler, spokesman for the Austrian National Olympic Committee, said the email was a hoax that officials had seen before.

“It’s a fake mail from a sender in Israel who has been active with various threats for a few years,” Eichler told Austrian news agency APA.

Germany’s national Olympic association, the DOSB, also said it had received “several times the same mail with unspecific, general warnings” and it had sent it onto security officials.

“We are not aware of any threats that have been deemed as credible being directed toward our delegation,” said British Olympic Association spokesman Darryl Seibel.

Across the Atlantic, some are viewing the Sochi Games with more trepidation. Members of Congress expressed serious concerns this week about the safety of Americans at next month’s Olympics in Russia and said Moscow needs to cooperate more.

While FBI Director James Comey said earlier in January that the Russian government “understands the threat and is devoting the resources to address it,” the U.S. has offered air and naval support to the Russian government as it conducts security preparations for the Olympics.

The State Department has advised Americans at the Olympics to keep vigilant about security because of potential terrorist threats, crime and uncertain medical care.