Crowds for European Championship soccer games are driving infections, the W.H.O. says.

Crowds gathering in stadiums, pubs and bars to watch the European Championship soccer games have driven a rise in coronavirus cases across Europe, the World Health Organization said on Thursday, raising concerns about another wave of infections even as vaccine rollouts have ramped up.

“We need to look much beyond just the stadiums themselves,” said Catherine Smallwood, the W.H.O.’s senior emergency officer. “We need to look at how people get there: Are they traveling in large, crowded convoys of buses? And when they leave the stadiums, are they going into crowded bars and pubs to watch the matches?”

In Scotland, more than 2,000 people tested positive after watching a Euro 2020 game either at a stadium, a fan zone or at a pub, according to National Health Scotland. (Nearly were two-thirds of those cases were linked to a Euro 2020 game in London in mid-June.) Around 120 fans from Finland were infected after traveling to St. Petersburg, Russia, to watch their team play.

After months of virus restrictions, and with the European Championships postponed for a year, soccer fans have been eager to travel across borders to watch the games in person. Finnish tourists attended games in Russia, French fans traveled to Romania, and Welsh ones supported their team in the Netherlands. In countries like Belgium, Britain and France, bars had reopened just weeks before the tournament began.

But given that most European countries have fully vaccinated less than a third of their populations, the risks are high. Experts say that the lax restrictions imposed on travel for the soccer championship may have serious consequences later in the summer or in the fall.

The rise in cases linked to the tournament comes more than a year after soccer games hosted early last year led to some of the first outbreaks in Europe.

Germany’s interior minister, Horst Seehofer, called the decision by European’s soccer governing body, UEFA, which runs the tournament, to allow large crowds in stadiums “utterly irresponsible.”

Despite the warnings by the W.H.O., Britain officials are allowing 60,000 fans to attend each of the tournament’s three final games in London next week.