The prominent Russian investigative newspaper Novaya Gazeta said Monday that its offices in Moscow had been targeted with a "chemical attack."
"In the morning a chemical attack was carried out on the building where our editorial office is located," the independent media outlet's editor-in-chief Dmitry Muratov said in a statement.
He added that law enforcement agencies are inspecting the "substance spilled in front of the entrance" and that the effects were so strong the pungent odor could be felt down the street.
Muratov did not explicitly state who he thought was behind the attack, but he noted that earlier Monday three NGOs had announced a legal case against Russian mercenary group Wagner over the torture and killing of a detainee in Syria "based on our articles."
Denis Korotkov, a Novaya Gazeta reporter, had written articles about Wagner, a murky group with Kremlin links that has been deployed in conflicts across Africa, the Middle East and Ukraine.
Novaya Gazeta, which was established in 1993, has suffered numerous attacks on its offices and journalists over the years.
In 2006 top journalist Anna Politkovskaya, who investigated President Vladimir Putin and the Kremlin's tactics in Russia's restive republic of Chechnya, was gunned down in the entrance hall of her apartment block in Moscow.
More recently, in 2017, Novaya Gazeta columnist Yulia Latynina fled Russia after a series of attacks that included her car being set on fire and a chemical being sprayed through a window of her house.
Muratov noted Latynina's case in his statement Monday, saying that those attacks came in the wake of articles about Putin ally Yevgeny Prigozhin, who has been linked to Wagner.
In another incident in 2018, a funeral wreath and a severed goat's head were left outside the investigative newspaper's offices with a note reading: "To Novaya Gazeta's chief editor. Greetings to you and Korotkov!"