US State Department Secretary Antony Blinken on Thursday requested the Americans living in Russia to leave the country "immediately", after the reporter was arrested in Moscow.

Taking to Twitter, Mr Blinken said, "We are deeply concerned over Russia's announcement it has detained a U.S. citizen journalist. The @StateDept's highest priority is the safety and security of U.S. citizens abroad. If you are a U.S. citizen living or travelling in Russia - please leave immediately."

These remarks came after an American reporter for Wall Street Journal (WSJ) Evan Gershkovich was arrested in Russia on espionage charges, according to Al-Jazeera.

In a statement, Mr Blinken said, "We are deeply concerned over Russia's widely-reported detention of a U.S. citizen journalist. We are in contact with the Wall Street Journal on this situation. Whenever a U.S. citizen is detained abroad, we immediately seek consular access, and seek to provide all appropriate support."

"In the strongest possible terms, we condemn the Kremlin's continued attempts to intimidate, repress, and punish journalists and civil society voices," the statement added.

Meanwhile, White House Press Secretary Karine Jean-Pierre also expressed concern over the arrest of Evan Gershkovich in Russia. She also stated that last night, White House and State Department Officials spoke with Gershkovich's employer, the Wall Street Journal.

"The Administration has also been in contact with his family. Furthermore, the State Department has been in direct touch with the Russian government on this matter, including actively working to secure consular access to Gershkovich," the press secretary said in a tweet.

"The targeting of American citizens by the Russian government is unacceptable. We condemn the detention of Gershkovich in the strongest terms. We also condemn the Russian government's continued targeting and repression of journalists and freedom of the press," she added.

She also stated that the US government should heed the warning to not travel to Russia.

US citizens residing or travelling in Russia should depart immediately, as the State Department continues to advise, Ms Pierre tweeted.

WSJ in a statement said, "The Wall Street Journal is deeply concerned for the safety of Gershkovich."

The Federal Security Service (FSB), a top KGB successor agency, said that the WSJ reporter was detained from the Ural Mountains city of Yekaterinburg while he allegedly tried to obtain classified information.

In a statement, the FSB said, "Gershkovich acting on the instructions of the American side, collected information constituting a state secret about the activities of one of the enterprises of the Russian military-industrial complex", read a WSJ report.

The FSB has also alleged that Mr Gershkovich "was collecting classified information about the activities of one of the enterprises of the Russian military-industrial complex that constitutes a state secret", according to Al-Jazeera.

The local media stated that he was covering the war in Ukraine and the Wagner mercenary group before getting detained.

The mention of the date of arrest was not there in its statement, however, Mr Gershkovich could be imprisoned for about 20 years if he gets convicted of espionage.

Ever since the Cold War, he is the first journalist from an American news organisation to be detained in Russia on suspicion of espionage, and his detention comes at a time of intense international concern due to the conflict in Ukraine, according to Al-Jazeera.

Mr Gershkovich covers Russia and Ukraine and was duly accredited as a journalist as a correspondent for the Wall Street Journal's Moscow office.

His most recent assessment, which was released last week, concentrated on the stagnation of the Russian economy in the face of Western sanctions.

The Wall Street Journal hired Evan Gershkovich, 31, who was formerly employed by AFP in Moscow. Before, he worked as a reporter for The Moscow Times, according to his bio in Wall Street Journal.