President Joe Biden said on Friday that there is no time for complacency, as the US announced that it is working with NATO-ally Slovakia to provide Ukraine with an advanced air defense system.

As the Russian military prepares for the next phase of this war, I have directed my Administration to continue to spare no effort to identify and provide to the Ukrainian military the advanced weapons capabilities it needs to defend its country, according to a statement released by the White.

Defense Secretary Lloyd Austin praised Slovakia for sending an air defense system to Ukraine. He said it was a strong testament to the commitment of the neighbors of Ukraine. The US will give Slovakia an American-made missile system in return for the transfer, according to Biden.

Austin said that the deployment of Patriot capabilities to Slovakia was in line with previous efforts to bolster NATO's defensive capabilities and to demonstrate our collective security requirements under the NATO treaty.

Austin said that the deployment did not have an end date as the US and Slovakia explore more permanent air defense solutions.

Zelenskyy had raised the S-300 system with Biden. The Washington Post reported that the S-300 can reach altitudes of up to 18 miles.

Biden said that the Russian military may have failed in its goal of capturing Kyiv, but it continues to wreak havoc on the Ukrainian people.

Zelenskyy called for the US to support a no-fly zone in his speech to Congress. Zelenskyy said that if this was too much to ask for, then Ukraine needed better anti-aircraft systems. The US and NATO don't like a no-fly zone because it would require them to shoot down Russian warplanes. This would lead to a direct confrontation between a number of nuclear powers.

Russia has struggled to make gains on the ground since launching a war against Ukraine. The Russian military has lost thousands of soldiers since the war began. Russia's offensive is now focused on the eastern region.

Russia began supporting the rebels in the east of the country after invading and annexing Ukraine. Russia began its invasion of Ukraine in February after eight years of fighting in the Donbas. NATO believes that Moscow will move to conquer the rest of the region in the days to come, as the rebels control roughly one-third of the region.

NATO Secretary-General Jens Stoltenberg said on Tuesday that Russia would launch an offensive in the Donbas.

In the coming weeks, we expect a further Russian push in the east and southern Ukraine, to try to take the entire Donbas and to create a land bridge to the occupied Crimea.

In an interview with NPR on Friday, NATO Secretary General Jens Stoltenberg warned that Russian President Vladimir Putin has not changed his goal of controlling Ukraine.