Several thousand woman protested at the Russian Embassy in the Lithuanian capital on Sunday, calling on Russian women to rise up and stop the war in Ukraine.

"Today we send the message for the mothers of Russian soldiers. You can stop this war ... If only you will go to the streets and say 'we don't want this war when we don't want our children to die'," march organiser Daiva Zeimyte said.

Protester Ineta Miliniene added: "We want to ask Russian women - stop war. You can do this. You can do this because it is your children dying."

Demonstrations against the conflict have been held around the world, including in Russia, where more than 5,500 protesters have been detained since Thursday, the OVD-Info monitoring group said.

A Ukrainian presidential adviser has said 3,500 Russian soldiers had been killed or wounded. Reuters was not able to verify the numbers. Western officials have said intelligence shows Russia suffering higher casualties than expected, but Russia has not released casualty figures.

Lithuania, together with its Baltic neighbours Latvia and Estonia, was ruled from Moscow until 1991. The three have since joined the European Union and NATO military alliance.

"I can't stay at home and do nothing," said Indre Gasenceviciene, bursting into tears as she spoke alongside her husband and her two children, aged 2-1/2 years and 6 months.