MOSCOW/KYIV — High-ranking US figures, many associated with US intelligence services or pharmaceutical companies, have helped with military biological studies in Ukraine, Russia's Defense Ministry has said.

The ministry has a document with names of all the key US officials supervising Ukraine's military biological programs, Igor Kirillov, chief of the Radiation, Chemical and Biological Defense Forces of the Russian Armed Forces, said on Saturday.

The participants include Kenneth Myers, former director of the Defense Threat Reduction Agency with the US Department of Defense, and Thomas Frieden, former director of the US Centers for Disease Control and Prevention, Kirillov said.

Kirillov said in June that the Pentagon admitted the United States had supported 46 biological research facilities in Ukraine.

The latest accusation came a day after the Kremlin said Russia had made significant progress toward "demilitarizing" Ukraine, one of the goals President Vladimir Putin declared before the Russia-Ukraine conflict broke out.

Kremlin spokesman Dmitry Peskov offered the assessment of Russia's military progress when asked about comments by Putin, who on Thursday said that Ukraine's defense potential was close to zero.

In a Sunday interview, Putin said Russia was ready to negotiate with all parties involved in the conflict in Ukraine but that Kyiv and its Western backers had refused to engage in talks.

Moreover, the West has poured tens of billions of dollars' worth of weapons into Ukraine, and US President Joe Biden last week promised a US Patriot air defense system.

In the latest supply, the US House of Representatives approved $45 billion of aid to Ukraine as the country's President Volodymyr Zelensky addressed a joint sitting of the House and the US Senate on Wednesday. The package, already passed by a Senate majority vote, was on its way to US President Joe Biden's desk for final approval.

On the battlefield, Russian shells pummeled the southern Ukrainian city of Kherson on Saturday, killing at least 10 people and injuring 55 in the city.

Zelensky, just back from his quick trip to Washington, posted photos of the wreckage on his social media accounts. The destruction came as Ukrainians were beginning Christmas celebrations that for many Orthodox Christians will culminate in the traditional celebration on Jan 7.

"This is not sensitive content — it's the real life of Kherson," Zelensky tweeted. Accompanying images showed cars on fire, bodies on the street and building windows blown out.

In another development, air raid sirens wailed in Kyiv and across all Ukrainian regions on Sunday morning, officials said.

Xinhua