Washington (AFP) - Ukrainian President Volodymyr Zelensky will meet US leader Joe Biden and address Congress in Washington on Wednesday after Vladimir Putin vowed to strengthen the Russian military in Ukraine.
The secretly arranged trip comes as the Russian president blamed the West for the "shared tragedy" of the war and said Moscow would develop its military's nuclear capabilities.
It will be Zelensky's first trip outside Ukraine since Russian forces invaded in February, when they planned for a rapid takeover of Kyiv and much of the country.
Zelensky's visit will "underscore the United States' steadfast commitment to supporting Ukraine for as long as it takes," White House spokeswoman Karine Jean-Pierre said.
It comes after nearly 10 months of a war has seen Russian forces halted by a stubborn Ukrainian army backed by Western arms, forced to retreat from captured territory and struggling to avoid further setbacks.
"On my way to the US to strengthen resilience and defense capabilities of (Ukraine)," Zelensky tweeted, confirming that he will make a speech to Congress in person.
Zelensky will visit the White House where Biden is to announce a new arms package worth almost $2 billion that a senior administration official said includes Patriot air defense missiles.
Patriot missiles are seen as crucial to help Kyiv fend off Russia's punishing missile and drone attacks on its infrastructure.
Kremlin spokesman Dmitry Peskov said Wednesday that new weapons deliveries would lead to an "aggravation of the conflict" and do not "bode well for Ukraine".
Patriot missiles for Ukraine
He added that Moscow does not expect Ukraine to change its stance on peace talks -- including refusing to negotiate while Putin is in power -- during the visit.
Speaking with senior military officials during a televised address, Putin said Moscow was not to blame for the invasion and agreed with an assessment that Russia needed a larger army.
"The combat capabilities of our armed forces are increasing constantly," Putin said, adding that Russia will also "improve the combat readiness of our nuclear triad".
"What is happening is, of course, a tragedy -- our shared tragedy.But it is not the result of our policy.It is the result of the policy of third countries," he added.
"We don't have any limits on funding.The country and the government is giving everything that the army asks for, everything," Putin said.
Zelensky is also expected to address a joint session of Congress, which House Speaker Nancy Pelosi said would be "a very special focus on democracy."
The visit was quietly planned, beginning with a telephone call between Biden and Zelensky on December 11, followed by a formal invitation a week ago and confirmation of the visit on Sunday.
Details of the visit leaked on Tuesday afternoon, with officials stressing to US media that there were still security concerns over Zelensky's travel.
Biden and Zelensky will discuss the arms and training provided by the United States and allies, sanctions and other pressure on Russia, and economic and humanitarian aid that Ukraine needs, the senior White House official said.
Frontline visit
"They will discuss every element of this conflict, including the situation on the battlefield and including the question of where the war goes from here," the official said.
The visit will send Putin "a strong message of unity and resolve from the White House, from Washington, from the free world, on behalf of all the nations supporting Ukraine," the official added.
But that does not include pressuring Zelensky into talks with Putin, the official stressed.
Zelensky flies to the United States after a risky visit to the frontline in Bakhmut, where both sides have endured heavy tolls in constant shooting and shelling over the past two months.
Brutal trench warfare and artillery battles around Bakhmut -- once known for its vineyards and salt mines -- have flattened large portions of the city and its surroundings.
"Here in Donbas, you're protecting all of Ukraine," Zelensky told Ukrainian fighters.
"This is not just Bakhmut, this is fortress Bakhmut," he said, handing out honors to Ukraine servicemen.
Soldiers gave Zelensky a Ukrainian flag with their names signed on it and asked him to present it to Biden and Congress.
Zelensky said they told him: "We have a difficult situation.The enemy is increasing their numbers.Our guys are braver, but we need more weapons."
