US President Joe Biden announced another package of military assistance for Ukraine, as dozens of civilians were evacuated from Mariupol’s besieged steelworks, the last pocket of resistance against Russian troops in the port city.

Worth $150 million, the latest security assistance would include artillery munitions and radars, Biden said, as the country braces for fresh bombardment by Moscow’s forces ahead of May 9, the day Russia celebrates the Soviet victory over the Nazis in World War II.

A senior US official said the aid included counter-artillery radars used for detecting the source of enemy fire as well as electronic jamming equipment.

Friday’s new batch brings the total value of US weaponry sent to Ukraine since the Russian invasion began to $3.8 billion.

The president urged Congress to further approve a huge $33 billion package, including $20 billion in military aid, “to strengthen Ukraine on the battlefield and at the negotiating table.”

The Pentagon meanwhile denied reports it helped Ukrainian forces sink the Russian warship Moskva in the Black Sea last month.

Pentagon spokesman John Kirby said the US had “no prior knowledge” of the plan to strike the ship, which sank leaving a still-unclear number of Russian sailors dead or missing.

While providing Ukraine with military aid, the United States has sought to limit knowledge of the full extent of its assistance to avoid provoking Russia into a broader conflict beyond Ukraine.

Biden, other G7 leaders, and Ukraine’s President Volodymyr Zelensky are to meet virtually on Sunday to discuss Western support for Kyiv.

On Friday Zelensky said “diplomatic options” were also under way to rescue Ukrainian soldiers from the Mariupol steelworks, as civilian evacuations continued.

The Russian defence ministry said 50 people were evacuated from the site, including 11 children.

It added they were handed over to the UN and Red Cross, which are assisting in the operation, and that the “humanitarian operation” would continue on Saturday.

About 200 civilians, including children, are estimated to still be trapped in the Soviet-era tunnels and bunkers beneath the sprawling Azovstal factory, along with a group of Ukrainian soldiers making their last stand.

Russia announced a daytime ceasefire at the plant for three days starting Thursday but the Ukrainian army said Russian “assault operations” had continued by ground and by air.

Ukraine’s Azov battalion, leading the defence at Azovstal, said one Ukrainian fighter had been killed and six wounded when Russian forces opened fire during an attempt to evacuate people by car.

Azov battalion leader Andriy Biletsky wrote on Telegram that the situation at the plant was critical.

“The shelling does not stop. Every minute of waiting is costing the lives of civilians, soldiers, and the wounded.”