A Russian teenage activist was among four people detained after she staged a protest outside the World Cup stadium in St. Petersburg wearing a bloodied shirt that she said was intended to draw attention to the country's problems, Reuters reported.
"We wanted to draw attention to the fact that no matter what you show foreigners, things on the inside aren't that good and pretty," 16-year-old Lika Petrovskaya told Reuters on July 3.
Russia has strived to put on its best face to host the world's most prestigious soccer tournament, with some participants expressing surprise at the leniency shown by the authorities during many of the festivities.
"No matter the pretty things that are shown, people in Russia are still suffering," Petrovskaya said.
OVD-Info, a human rights organization that monitors detentions, said that three other activists, including two minors, had been detained along with Petrovskaya outside the stadium on July 3.
The local branch of the Interior Ministry could not immediately be reached for comment.
Petrovskaya lay for a few minutes at the foot of a statue of Zabivaka, the wolf that serves as the tournament's mascot, outside the St. Petersburg venue where Sweden beat Switzerland 1-0 in their second-round match on July 3.
She said she was not detained the first time she lay down by the statue, despite the presence of security officers, and voluntarily stepped away when tourists asked her to move so they could take a picture. But she said she was detained by police when she returned for a second attempt.
Petrovskaya said one the issues she was protesting was the imprisonment of Ukrainian filmmaker Oleh Sentsov, who is being held in a Siberian jail where he has been on a hunger strike for 40 days.
Sentsov was sentenced to 20 years in a maximum-security prison in 2015 after being found guilty of setting fire to two offices in Crimea after Moscow annexed the territory from Ukraine.
A native of Crimea, Sentsov and human rights groups say the charges were politically motivated.
The protest in St. Petersburg wasn't the first during the games. Russian activists last week held a covert protest on a central Moscow street popular with World Cup fans to call on the Kremlin to release Sentsov.
And opposition parties during the games staged protests around the country against the Kremlin's plan to raise the retirement age.
Meanwhile, Moscow police said on July 3 that they had detained a person who vandalized a statue of a renowned Soviet soccer player outside the Spartak stadium where England was playing Colombia in a match.
The word "England" was painted in red on the chest of a statue of Fyodor Cherenkov, a former Soviet national team player and Spartak Moscow midfielder who died in 2014, according to pictures posted on social media during the match.
Police said in a statement they "had identified and detained" the person who vandalized the statue, which is located near the stadium's main entrance. The police statement did not disclose the vandal's identity, or say whether he or she was a British national.
England beat Colombia 4-3 on penalty kicks and will face Sweden in the quarterfinals in Samara on July 7.