Russia's defence ministry has given its first figures for casualties sustained during its invasion of Ukraine.
It says 498 Russian soldiers have been killed and 1,597 wounded so far, according to Russian media reports.
The claim is significantly less than Ukraine's assessment of Russian casualties - Kyiv claims it has killed 5,840 Russian troops.
Russia has also claimed that more than 2,870 Ukrainian service members have been killed and about 3,700 wounded. Kyiv has not given any figures.
Earlier Ukraine's emergency services said more than 2,000 civilians and 10 emergency services personnel had been killed so far.
Why it's so difficult to count victims in war
One challenge in this conflict has been to independently confirm an accurate number of victims.
Russia and Ukraine both say they have killed thousands of opposing troops. Now Moscow says nearly 500 of its soldiers have been killed, while Ukraine has not yet given an updated figure for military casualties but says at least 2,000 civilians have died.
Why should we be sceptical about claims?
In a war, countries use information as part of their strategy. It helps galvanise support for a cause or, in the case of losses, opposition to it. So there can be a lot of disinformation around.
Ukraine, which has enjoyed widespread support from countries around the world, is keen to show the scale of the destruction and human suffering caused by Russia's unprovoked aggression.
For Russia, news of mass casualties among Russian troops, and the Ukrainian population, could potentially spread the anti-war sentiment even further and turn into an existential threat to President Vladimir Putin's rule.
So who is a reliable source?
The UN and human rights groups are often the go-to sources for accurate estimates. But they too have been struggling.
Many of their teams have had to relocate and the security situation means that in many cases they are unable to visit places attacked to investigate them.
Numbers are released only after workers corroborate information from multiple sources, including survivors, witnesses, open source investigation, and reports from authorities or other organisations.
That takes time, and that is why UN figures are often below other estimates, including those from governments.
On Tuesday, the agency estimated that at least 136 civilians had been killed so far. But the real number, spokeswoman Liz Throssell warned, was "likely to be much higher".
