Ukrainian President Volodymyr Zelenskyy thanked the British people on Wednesday for their support since "Day One" of Russia's invasion, as he addressed U.K. lawmakers during a rare trip outside his country to seek more support.

"I have come here and stand before you on behalf of the brave," the president said, paying tribute to Ukraine’s military. "I thank you for your bravery ... London has stood with Kyiv since Day One."

House of Commons Speaker Lindsay Hoyle said that lawmakers were honored that Zelenskyy had put himself at risk to make the address.

Zelenskyy's daring to visit Britain in a bid for more advanced weapons comes as Kyiv braces for an expected Russian offensive and hatches its own plans to retake land held by Moscow's forces.

Hundreds of lawmakers and parliamentary staff packed the 900-year-old Westminster Hall, the oldest - and unheated - part of Parliament for Zelenskyy’s speech. It was only his second confirmed journey outside Ukraine since Russia invaded nearly a year ago.

Zelenskyy has rallied support for his country repeatedly through such speeches – mostly given remotely – to Western lawmakers. Support from allies has helped Ukraine mount a surprisingly stiff defense - and now the two sides are engaged in grinding battles.

The Ukrainian leader arrived on a Royal Air Force plane in London on Wednesday. Prime Minister Rishi Sunak greeted him on the tarmac, tweeting a photo of him embracing the Ukrainian leader.

"The United Kingdom was one of the first to come to Ukraine’s aid. And today I’m in London to personally thank the British people for their support," Zelenskyy said on Instagram.

A large convoy of vehicles left the airport and headed straight to Downing Street in central London. Both leaders posed briefly for photos in front of the famous black door that leads into the U.K. prime minister's residence.

The U.K. is one of the biggest military backers of Ukraine and has sent the country more than 2 billion pounds ($2.5 billion) in weapons and equipment.

The visit comes as Sunak announced that Britain will train Ukrainian pilots on "NATO-standard fighter jets." Ukraine has urged its allies to send jets, though the U.K. says it’s not practical to provide the Ukrainian military with British warplanes.

More than 10,000 Ukrainian troops have also been trained at bases in the U.K., some on the Challenger 2 tanks that Britain is sending.

"I am proud that today we will expand that training from soldiers to marines and fighter jet pilots, ensuring Ukraine has a military able to defend its interests well into the future," Sunak said.

Coinciding with the visit, the U.K. government announced a new round of sanctions against six entities that Britain said supplied equipment to the Russian military.

CST, a manufacturer of Russian drones and parts for helicopters used against Ukraine, were among those sanctioned. Others targeted included five individuals linked to Russian President Vladimir Putin’s luxury residences, including Boris Titov and Aerostart owner Viktor Myachin.

Zelenskyy addressed the U.K. Parliament remotely in March, two weeks after the start of the invasion. He echoed World War II leader Winston Churchill’s famous "never surrender" speech, vowing that Ukrainians "will fight till the end at sea, in the air. We will continue fighting for our land, whatever the cost."

Before Sunak took office, Zelenskyy had formed a bond with Boris Johnson, who was one of Ukraine’s most vocal backers while he was prime minister. Sunak took office in October and has pledged to maintain the U.K.’s support.

Zelenskyy visited the U.S. in December.

On Wednesday, he may be seeking Western pledges of more advanced weapons before potential spring offensives by both Russia and Ukraine. Zelenskyy will also meet with King Charles III and U.K. military chiefs during his visit.

Next stop Brussels?

In Brussels, there were increasing expectations that the Ukrainian leader might also make his first visit to European Union institutions since the war began.

Leaders from the 27-nation bloc will gather for a Brussels summit on Thursday. That would enable Zelenskyy to meet with all major leaders of the bloc in one day. Zelenskyy has often addressed EU summits only through video calls from Ukraine.

The EU's legislature has also slated a special plenary session in Brussels for Thursday in the hopes that Zelenskyy will come following his trip to Britain.

The London visit came as Russian forces blasted areas of eastern Ukraine with more artillery bombardments, Ukrainian officials said Wednesday, in what Kyiv authorities believe is part of a new thrust by the Kremlin’s forces before the invasion anniversary.

Russian forces over the past day launched major shelling attacks on areas near the front line in Ukraine’s northeastern Kharkiv region, killing a 74-year-old woman and wounding a 16-year-old girl in the border town of Vovchansk, local Gov. Oleh Syniehubov said.

Russian forces in Ukraine are focusing their efforts on "waging a counteroffensive" in the country’s industrial east, with the aim of taking full control of the Donetsk and Luhansk regions that make up the Donbas, the General Staff of the Armed Forces of Ukraine said.

Russian troops launched assaults near Bakhmut and Vuhledar, two mining towns in the Donetsk region that have been among Moscow’s key targets, Ukrainian officials said.

Seizing Bakhmut could severely disrupt Ukraine’s military supply routes. It would also open a door for Moscow’s forces to drive toward key Ukrainian strongholds in Donetsk.

Ukrainian authorities say the Kremlin’s goal is to complete full control of the Donbas, an expansive industrial area bordering Russia. That would give Russian President Vladimir Putin a major battlefield success after months of setbacks and help him rally public opinion behind the war.

Military analysts say that after a Ukrainian counteroffensive that started last summer and recaptured large areas from Russia, the war has been largely static in recent months.

Moscow, meanwhile, believes Ukraine is preparing its own battlefield push.

The Russian-installed leader of the occupied Luhansk region said Wednesday the situation in some areas is "very difficult" because Kyiv is mustering forces for a counterattack.

Leonid Pasechnik told Russian state TV that the situation is "very difficult" in areas around a key Russian supply route. "Unfortunately, the enemy is accumulating sufficient reserves there, forces to counterattack, to return the lost territories," he said.

It wasn't possible to verify the claims by the two sides.