Russian president Vladimir Putin has urged both sides in the Ukrainian conflict to sit down at the negotiating table and find a compromise.
He said such a compromise must guarantee the rights of Russian-speaking residents of eastern Ukraine, who must feel like they are "an integral part" of Ukraine.
More top news
The memorial service will be attended by Prince Harry and Meghan Markle.
David Browning admits manslaughter by diminished responsibility but denies murder.
Four people have died and the suspect is still at large, police said.