The United Nations welcomes the unilateral ceasefires announced by Ukraine and Russia, said a UN spokesperson on Tuesday.

"We welcome the unilateral ceasefire announced by Ukraine, to begin on the night of May 5 to 6, as well as the one by the Russian Federation, to take place over May 8 and 9," said Stephane Dujarric, spokesman for UN Secretary-General Antonio Guterres.

Dujarric told a daily press briefing that the secretary-general looks forward to their successful implementation, and reiterates his call for a full, immediate, unconditional and lasting ceasefire, leading to a just, comprehensive and sustainable peace, in line with the UN Charter, international law and relevant UN resolutions.

Russia's Defense Ministry on Monday declared a Victory Day ceasefire on May 8-9. Ukrainian President Volodymyr Zelenskyy announced Monday night that Ukraine will start a ceasefire with Russia starting Wednesday. He did not set an end date for the truce.

Read more: Russia, Ukraine declare ceasefire around Victory Day commemorations

Moscow announced a temporary ceasefire over last month's Orthodox Easter holiday, yet Russia and Ukraine each blamed the other for breaking it.

(With input from Xinhua)