He stated this at a hearing at the Select Committee on Intelligence of the US Senate. 

“Our assessment is that Russia today is not serious about negotiations,” Burns said.

He also noted that US assistance will help the Ukrainian Armed Forces launch an offensive at the end of 2024.

In addition, according to him, US assistance will give the Ukrainian Armed Forces the opportunity to strike at Crimea.

In September 2022, the press secretary of the Russian president, Dmitry Peskov, said that Crimea is an integral part of Russia and claims to Russian territory will receive a proper response. 

Russian leader Vladimir Putin has repeatedly emphasized that the issue of Crimea is closed for Russia, and the referendum on the peninsula was held in strict accordance with international law. 

Crimea became a Russian region after a referendum took place there in March 2014: the majority of residents were in favor of reunification with Russia.