Seven people linked to a Kremlin-funded media outlet in Azerbaijan’s capital were arrested after police raided its office, according to local media quoting the Interior Ministry on Tuesday in the latest sign of rising tensions between Moscow and Baku after the deaths of two ethnic Azerbaijanis in Russian custody.

The tensions escalated since December when an Azerbaijani passenger plane came under attack while trying to land in Grozny, the capital of Chechnya in Russia and later crashed, killing 38 of the 67 people on board. President Ilham Aliyev blamed Moscow and said Russian President Vladimir Putin had attempted to "hush up" the tragedy.

On Monday, masked police entered the office of Sputnik Azerbaijan, and the Interior Ministry said the Kremlin-supported media outlet had continued working through "illegal funding" even after its accreditation was cancelled in February.

Those arrested included Sputnik Azerbaijan’s editor in chief, Yevgeny Belousov and editorial board head, Igor Kartavykh, along with five others connected to the organisation who were also detained and are now under investigation for fraud, illegal business activities and possessing property obtained through criminal means.

Belousov and Kartavykh were charged with conspiracy to commit fraud, which is punishable by up to 12 years in prison and were also accused of conspiracy to launder money or property and of running an unauthorised business, with both being placed in pre-trial detention for a minimum of four months.

Rossiya Segodnya, which owns Sputnik, said on Tuesday it was "deeply concerned" about the raid and confirmed that Azerbaijani staff members were among those detained and also reported that Russian diplomats were not allowed to meet the arrested citizens and that Kartavykh’s apartment had been searched and his computer equipment taken.

"All these steps are groundless and resulted in blocking Sputnik Azerbaijan", the statement reads "We urge the Azerbaijani authorities to resolve this unacceptable situation immediately and free our colleagues."

The Kremlin also demanded that those arrested be released.

"Measures against the members of the media like this are completely not in accordance with the universally accepted rules and norms and naturally do not correspond to the spirit and character of Russian Azerbaijani relations", Kremlin spokesman Dmitry Peskov said on Tuesday.

The arrests came after Russian police on Friday raided the homes of ethnic Azerbaijanis in Yekaterinburg as part of an investigation into several killings from past decades, and during these raids, two brothers, Ziyaddin and Huseyn Safarov, died while in police custody and several others were seriously injured and nine people were detained according to officials.

Sayfaddin Huseynli, the brother of the two deceased men, told The Associated Press that the raids were "an inhumane, cruel act by Russia against migrants — an act of intimidation."

Migrants from former Soviet republics with Muslim majority populations often say they face discrimination in Russia.

On Tuesday, Azerbaijan’s Prosecutor General’s Office said it would open a criminal investigation into the two deaths and stated that Azerbaijani citizens and others of Azerbaijani descent who were "practically helpless and unable to defend themselves" were beaten and physically mistreated by Russian officials.

The office said that 60-year-old Huseyn Safarov and 55-year-old Ziyaddin Safarov died from "post-traumatic shock caused by multiple injuries", and also said that Huseyn had suffered from post-hemorrhagic shock.

Russia’s Investigative Committee said on Monday that one of the deaths was due to heart failure and stated that a medical examination would be conducted to find the cause of death in both cases, but gave no further details about the second victim.

As a protest over the deaths, Azerbaijan cancelled a planned official visit to Moscow and accused Russian law enforcement of "targeted extrajudicial killings and violence against Azerbaijanis on the basis of their nationality" and also postponed a scheduled visit to Baku by a Russian deputy prime minister, while the Culture Ministry cancelled concerts exhibitions and other events organised by Russian state or private institutions.

Relations between Moscow and Baku have remained tense since the Azerbaijani plane crash in December, which happened as the plane tried to land in Kazakhstan.

Aliyev said the plane was attacked over Russian territory, though by accident and became uncontrollable due to electronic warfare and indicated that Russian air defence systems may have been responding to a Ukrainian drone near Grozny while Putin later apologised and called it a "tragic incident" but did not accept responsibility.

In May, Aliyev skipped the Victory Day parade in Moscow, and later that month, Ukrainian Deputy Foreign Minister Andrii Sybiha visited Baku in what was seen as a sign of closer ties between Azerbaijan and Ukraine.

Ukrainian President Volodymyr Zelenskyy also called Aliyev to offer his condolences over the two deaths in Yekaterinburg, according to a statement from Azerbaijan’s presidential press service.