(CNN) President Joe Biden spoke with Ukrainian President Volodymyr Zelensky on Monday after a deluge of Russian missiles targeted cities across Ukraine, condemning the strikes and pledging continued US security assistance "including advanced air defense systems."
During the call, a White House statement said, Biden "expressed his condemnation of Russia's missile strikes across Ukraine, including in Kyiv, and conveyed his condolences to the loved ones of those killed and injured in these senseless attacks. President Biden pledged to continue providing Ukraine with the support needed to defend itself, including advanced air defense systems."
The White House did not specify which air defense systems Biden discussed with Zelensky, but the United States previously committed to providing Ukraine with National Advanced Surface-to-Air Missile Systems. NASAMS would be capable of engaging Russian cruise missiles.
Biden, the statement said, "also underscored his ongoing engagement with allies and partners to continue imposing costs on Russia, holding Russia accountable for its war crimes and atrocities, and providing Ukraine with security, economic, and humanitarian assistance."
Asked whether the attacks of the past 24 hours would change the calculus on what the US would consider offering Ukraine, a senior administration official said they had no announcements to make on that front, but that the US will continue to help provide Ukraine with short- and long-range air defense systems, as it has in the past.
And a second senior administration official provided the following summary of air defense aid provided to Ukraine from the US: "We have transferred more than 1,400 Stinger anti-air systems to Ukraine, as well as air surveillance and multi-mission radars. We enabled our Allies to transfer air defense systems of their own to Ukraine -- including Slovakia's transfer of a critical S-300 system in April. And in August, President Biden announced a new assistance package for Ukraine that included orders for 8 new NASAMS—National Advanced Surface to Air Missile Systems. We will continue to provide Ukraine with what it needs to defend itself."
As of a Department of Defense briefing in late September, the US had yet to deliver NASAMS to Ukraine. At the time, Brig. Gen. Patrick Ryder said two systems were expected to be delivered in the next two months, with the remaining six to arrive at an undetermined date.
Secretary of State Antony Blinken also spoke with Ukrainian Foreign Minister Dmytro Kuleba on Monday to reiterate US support following the deadly strikes. Biden is expected on Tuesday to join an emergency video conference with G7 leaders during which Zelensky is expected to address the group.
Russia launched a total of 84 cruise missiles against targets across Ukraine on Monday, the General Staff of the Armed Forces of Ukraine said in a Facebook post.
Russian President Vladimir Putin said the strikes were a response to what he described as acts of "terrorism" by Kyiv. Specifically, he referred to Saturday's explosion on the Kerch Bridge linking Russia and Crimea -- which he blamed on Ukraine's "special services" -- and a list of other alleged "crimes."
Kuleba said that such claims were "nonsense," writing in a tweet, "Putin is desperate because of battlefield defeats and uses missile terror to try to change the pace of war in his favor." And Ukraine's defense intelligence agency claimed in a statement on Monday that Moscow had been planning a "massive" missile attack on Ukraine since early last week.
Dmitry Medvedev, the deputy head of Russia's Security Council, also recently said he thinks Moscow should aim for the "complete dismantling" of Zelensky's "regime."
In a post on Telegram, Medvedev -- who served as President of Russia between 2008 and 2012 -- said: "The Ukrainian state in its current configuration ... will pose a constant, direct and clear threat to Russia. Therefore, in addition to protecting our people and protecting the borders of the country, the goal of our future actions, in my opinion, should be the complete dismantling of the political regime of Ukraine."
John Kirby, a spokesperson for the National Security Council, said Monday that there will likely be additional support packages for Ukraine announced "in the very near future."
"It's clear that he's feeling the pressure both at home and overseas, and how he reacts to that only he can say," Kirby told CNN's Kate Bolduan on "Erin Burnett OutFront."
Kirby added: "He understands well that he's not doing well on the battlefield."
Asked if he thinks such strikes make it more likely Putin would resort to nuclear weapons, Kirby said that the US has seen nothing new.
"We continue to monitor his nuclear capabilities, Kate, best we can. And what I can tell you today is that we just don't see any indications that Mr. Putin has made a decision to use weapons of mass destruction or even nuclear weapons. And we've seen nothing, Kate, that would give us cause to change our own deterrent posture," Kirby said.
The mention of air defense system comes amid a series of escalations in the war.
Putin last month delivered a speech announcing the partial mobilization of some 300,000 reservists following successful Ukrainian counterattacks, raising the specter of nuclear weapons if he deemed the "territorial integrity" of Russia to be jeopardized. And the Russian president recently announced the annexation of four Ukrainian regions in defiance of international law.
Last week, Biden delivered a stark warning about the dangers of Putin's nuclear threats, invoking the prospect of "Armageddon." But multiple US officials have said the comment was not based on any new intelligence about Putin's intentions or changes in Russia's nuclear posture.
This story has been updated with additional information Monday.