Volodymyr Zelenskiy to meet US secretary of state Antony Blinken in Kyiv on Sunday as Russia continues attacks on southern and eastern Ukraine

• Russia-Ukraine war: latest updates

The US secretary of state, Antony Blinken, and defence secretary, Lloyd Austin, will travel to Kyiv to meet the Ukrainian president, Volodymyr Zelenskiy, on Sunday. It will be the first high-level US trip to the city since the war began on 24 February.

Zelenskiy, at a press conference on Saturday held in an underground metro station, said Ukraine will ask the US for more heavy weapons to defeat Russia. “As soon as we have [more weapons], as soon as there are enough of them, believe me, we will immediately retake this or that territory, which is temporarily occupied,” Zelenskiy said.

Ukraine’s president also spoke at length about possible peace negotiations with Russia, saying if Moscow kills any Mariupol defenders – or goes forward with the independence referendum in the partly occupied southern regions of Kherson and Zaporizhzhia – Ukraine will suspend peace negotiations with Moscow.

In attacks on the eve of Orthodox Easter, Russian forces pounded cities and towns in southern and eastern Ukraine. A three-month-old baby was among eight people killed when Russia fired cruise missiles at the Black Sea port city of Odesa, officials said. Eighteen more were wounded.

Separate strikes in Girske, a village in the eastern Lugansk region, killed six civilians, the region’s governor, Sergiy Gayday, said.

Two Russian generals were killed near Kherson, the Ukrainian ministry of defence said in a statement. Another is in critical condition. The Ukrainian military on Friday hit the command post of Russia’s 49th army near the occupied regional capital, the ministry said.

The fate of the Ukrainians in the sprawling and besieged steel mill in Mariupol wasn’t immediately clear. Earlier Saturday, a Ukrainian military unit released a video reportedly taken two days earlier in which women and children holed up underground, some for as long as two months, said they longed to see the sun.

Another attempt to evacuate women, children and older adults from Mariupol failed on Saturday. Petro Andryushchenko, an adviser to Mariupol’s mayor, said Russian forces did not allow Ukrainian-organised buses to take residents to Zaporizhzhia, a city 227km (141 miles) to the north-west.

The US-based Institute for the Study of War has released its latest analysis, warning that Russian forces will likely increase the scale of ground offensive operations in the coming days. It predicts that Russia will likely continue attacking south-east from Izyum, west from Kreminna and Popasna, and north from Donetsk via Avdiivka or another axis. Russian forces will attempt to starve out the remaining defenders of the Azovstal steel plant in Mariupol and will not allow trapped civilians to evacuate, it adds.

Satellite images released this week showed what appeared to be two recently excavated mass grave sites next to cemeteries in two towns near Mariupol, and local officials accused Russia of burying thousands of civilians to conceal the slaughter taking place there. The Kremlin has not commented on the images.

Russia said it took control of several villages elsewhere in the eastern Donbas region and destroyed 11 Ukrainian military targets on Saturday, including three artillery warehouses. Russian attacks also struck populated areas.

The UK Ministry of Defence released an intelligence update detailing accusations that Russia is planning to conscript Ukrainian civilians in the Kherson and Zaporizhzhia regions.

Nearly 5.2 million people have fled Ukraine due to the war. The number of Ukrainians leaving the country since Russia’s invasion is now 5,163,686, the UN refugee agency says.

A third of Russian gas exported to the European Union could be affected because of the war, says the head of Ukraine’s state gas company Naftogaz.

Reuters, the Associated Press and Agence France-Presse contributed to this report