Nearly three weeks have passed since Russia began its invasion of Ukraine. US officials say Russian forces are using more long-range weapons, without any apparent concern over what they hit.

Ukraine's capital Kyiv was under attack early on Tuesday. Airstrikes also continue in the country's west. Foreign media outlets quote local officials as saying a missile attack on a TV tower near the city of Rivne cut off broadcasts on Monday. At least 9 people were reported killed and 9 others injured.

The United Nations says at least 636 civilian deaths have been confirmed since the invasion began, including 46 children. More than 2.8 million people have fled to other countries.

A senior Pentagon official said on Monday that Russian forces had fired more than 900 missiles. The official said the Russian military is apparently trying to subdue population centers by using long-range weapons, which are increasingly indiscriminate in what they strike.

The US official says Ukrainians are showing fierce resistance but the Russians still appear to have about 90 percent of their combat capabilities.

Foreign fighters in countries such as Syria are signing up to join Russia's side. Human rights monitors there say the campaign has attracted more than 40,000 recruits. One of the fighters said, "I want to get out of poverty. I want to have a future, and bread. I don't want to miss this chance to support my family."

Talks continue between Ukraine and Russia. Negotiators spoke via video link on Monday. Ukrainian President Volodymyr Zelenskyy said, "I've been briefed that the negotiations toward ceasefire and peace went pretty well." The talks were slated to continue on Tuesday.