MOSCOW (AP) — Police in Russia raided the home of the chief editor of an investigative media outlet that was recently designated as a “foreign agent,” the latest step by authorities to raise pressure on independent media ahead of the country's September parliamentary election.

Roman Dobrokhotov, chief editor of The Insider news site, tweeted on Wednesday morning that “police are knocking" on the door of his apartment. “Looks like it's a raid,” Dobrokhotov said.

OVD-Info, a legal aid group that monitors political arrests, said Dobrokhotov's wife called the group's hotline and reported a police raid before her phone became unavailable. A lawyer headed to Dobrokhotov's apartment, OVD-Info said.

Russian opposition supporters, independent journalists and human rights activists have faced increased government pressure ahead of September's voting, which is widely seen as an important part of President Vladimir Putin’s efforts to cement his rule before a 2024 presidential election.

The 68-year-old Russian leader, who has been in power for more than two decades, pushed through constitutional changes last year that would potentially allow him to hold onto power until 2036.

In recent months, the government has designated several independent media outlets and journalists as "foreign agents" — a label that implies additional government scrutiny and carries strong pejorative connotations that could discredit the recipients.

The targeted outlets include VTimes and Meduza. VTimes subsequently shut down, citing the loss of advertisers, and Meduza launched a crowd-funding campaign after encountering the same problem.

The Insider, which is registered in Latvia and has published investigations into alleged corruption and abuses by Russian officials, purported Russian covert action in Ukraine and Syria, and the poisoning of Russian opposition leader Alexei Navalny, was the latest addition to the list.

The Justice Ministry acted under a law that is used to designate as foreign agents non-governmental organizations, media outlets and individuals who receive foreign funding and engage in activities loosely described as political.

In comments to the media, Dobrokhotov has said The Insider would continue to operate as usual, in accordance with Latvian laws, and would not comply with the requirements of the foreign agents law.

Russia used the law to levy heavy fines on U.S.-funded broadcaster Radio Free Europe/Radio Liberty for failing to identify its material as produced by foreign agents. The broadcaster has asked the European Court of Human Rights to intervene.