(The Hill) – Secretary of State Antony Blinken on Thursday confirmed that a U.S. citizen was killed in Ukraine.

Blinken said during a briefing that he had no further details about the incident yet.

The Pentagon would not confirm the death, while the State Department told The Hill no more details could be shared at this time.

Police in the Ukrainian region of Chernihiv said in a Facebook post that an American was among the people killed by a heavy artillery attack but did not detail where in the city the attack occurred.

Chernihiv, located in the northeast of Kyiv, has been under heavy bombardment from Russian forces with its governor estimating that 53 people were brought to morgues in the past 24 hours, the Associated Press reported.

The news follows the death of U.S. journalist Brent Renaud, an independent filmmaker who had previously contributed to The New York Times.

Russia invaded Ukraine on Feb. 24, launching a full-scale assault that has faced stiff resistance from Ukrainian forces heading into the fourth week of the campaign.

The U.S. has said it will not put troops on the grounds and has resisted calls for a no-fly zone over Ukraine over fears it could spark a larger conflict with Russia.

The Department of State issued do not travel advisories to U.S. citizens for Belarus, Russia and Ukraine.

Laura Kelly and Ellen Mitchell contributed.