Secretary of State Antony Blinken on Thursday accused Vladimir Putin of committing war crimes and using terror tactics while suggesting the Russian leader might be planning to deploy chemical weapons in Ukraine.

In a news briefing in Washington, Blinken said he agrees with President Joe Biden’s assessment Wednesday that Putin is a war criminal for leading Russia’s assault on Ukraine, which has led to at least 780 civilian deaths, according to the United Nations.

“Intentionally targeting civilians is a war crime. After all the destruction of the past three weeks, I find it difficult to conclude that the Russians are doing otherwise,” said Blinken, who cited attacks on a maternity hospital last week in Mariupol, a theater being used as a civilian shelter Wednesday in Mariupol and a bread line Wednesday in Chernihiv. 

Blinken said U.S. officials are “documenting and evaluating potential war crimes being committed in Ukraine.”

“We'll make sure that our findings help international efforts to investigate war crimes and hold those responsible accountable,” he said.

Just as he did in a speech to the United Nations Security Council shortly before the war broke out, Blinken listed Russian actions that U.S. intelligence officials “have a strong sense” could be next. 

The secretary of state said the U.S. believes “Moscow may be setting the stage to use a chemical weapon and then falsely blame Ukraine to justify escalating its attacks on the Ukrainian people.” It’s a strategy Russia previously used in Georgia, Blinken said.

He also said Russia might bring mercenaries from private military groups in foreign countries to fight in Ukraine.

And Blinken also said Moscow is “likely to systematically kidnap local officials and replace them with puppets,” which he called a “terror tactic.”

Last week, two Ukrainian mayors — Melitopol’s Ivan Fedorov and Dniprorudne’s Yevhen Matveyev — were abducted by Russian soldiers. 

Fedorov was freed Wednesday — a Ukrainian news agency, quoting a senior official, reported that he was swapped for nine Russian prisoners. Matveyev has not be let go.

Meanwhile, Blinken said, the U.S. is focused on trying to end the war by providing military aid, supporting diplomatic efforts and imposing sanctions. While he commended Ukraine for continuing to hold talks with Kremlin officials, he said he has not “seen any meaningful efforts by Russia to bring this war that it’s perpetrating to a conclusion through diplomacy.” 

Blinken also paid his respects to journalists who were killed or wounded in Ukraine over the past week, including Fox News correspondent Benjamin Hall, who was injured Monday when the vehicle he was traveling in came under fire outside of Kyiv. The secretary of state said he has gotten to know Hall, 39, when he’s been a member of the traveling press corps.

“He's an incredibly talented reporter, always asking tough questions,” Blinken said. “He's a lovely person as well. Our thoughts, my thoughts are with him and his family, including his three little kids.”

Two other journalists working for Fox were killed in the same attack: cameraman Pierre Zakrzewski, 55, and Oleksandra "Sasha" Kuvshynova, a 24-year-old Ukrainian consultant who was helping the crew navigate the region. Blinken acknowledged them, as well as Brent Renaud, a filmmaker and journalist on assignment for Time magazine, who was fatally shot Sunday in the Kyiv suburb of Irpin.

“Being a war correspondent is vital work,” Blinken said. “They make sure that the world knows what's really happening when armies move in and bombs start falling. It also takes incredible courage.”

Blinken also confirmed another American citizen has been killed in Ukraine, but he did not provide any details.