Biden call to allies kicks off crucial week for West's Ukraine strategy

US President Joe Biden discussed Russia's "brutal" war in Ukraine in a phone call with European allies Monday ahead of attending NATO and EU summits, followed by a trip to Poland, in a crucial week for the West's standoff with Moscow.

The White House said Biden hosted the call, lasting just under one hour, with French President Emmanuel Macron, German Chancellor Olaf Scholz, Italian Prime Minister Mario Draghi and UK Prime Minister Boris Johnson "to discuss their coordinated responses."

"The leaders discussed their serious concerns about Russia's brutal tactics in Ukraine, including its attacks on civilians," a White House statement said.

"They underscored their continued support for Ukraine, including by providing security assistance to the brave Ukrainians who are defending their country from Russian aggression, and humanitarian assistance to the millions of Ukrainians who have fled," it said.

Later, Biden was joining prominent CEOs in Washington at a roundtable where the economic squeeze on Russia -- and likely the complications for US businesses -- is also on the table.

This kicks off the most momentous foreign trip of Biden's presidency so far, with Thursday's summits in Brussels and talks with President Andrzej Duda in Poland, on the frontline of the West's confrontation with Russia, Saturday.

Russia's war is about to enter its second month, and US and Western allies have imposed unprecedented sanctions on Moscow, crippling the ruble and stock market, while going after President Vladimir Putin's wealthy supporters.

On the ground in Ukraine, Western-supplied weapons, backed by years of training and funding, have helped the country's military to bloody the Russian invaders on multiple fronts.

White House Press Secretary Jen Psaki said that Biden's diplomatic emphasis had been on "unity" and on his trip "what the president is hoping to achieve is continued coordination."

However, with the war starting to look like a stalemate, Ukrainian President Volodymyr Zelensky is making increasingly desperate appeals for the West to do more.

What those additional steps could be remains far from obvious, as Biden and his European allies ponder blowback from their sanctions on Russia and also the danger of wider war if they expand military assistance to Ukraine.

One big hole in the sanctions regime is China, the world's second biggest economy. Beijing is refusing even to condemn ally Russia and a nearly two-hour talk between Biden and his Chinese counterpart Xi Jinping on Friday appeared to result in no change.

While the sanctions have sent severe shockwaves through Russia's economy, US and especially European economies -- which rely heavily on Russian energy imports -- are likewise vulnerable.

The United States and Britain have already announced their own bans on Russian oil imports. A wider ban by EU countries would mark a huge escalation hurting Moscow -- but also Western consumers.

Brent North Sea crude traded at $114.55 a barrel early Monday and earlier this month hit $139, up from about $79 at the beginning of the year.

A broad oil embargo "will hit everyone," Kremlin spokesman Dmitry Peskov warned.

Neither is there an easy path to significant changes to Ukraine's military.

Zelensky is pleading for more powerful tools beyond the effective but limited anti-tank rockets and Stinger missiles used to hit low flying aircraft.

But Biden has firmly rejected Zelensky's calls for a NATO-imposed no-fly zone, saying this would require the United States to go to war against Russia.

The alliance has also stumbled over a failed push by Poland to send Soviet-designed MiG-29 fighter jets to Ukraine through a US air base. Again, Washington said this would risk Russia declaring that NATO had actively entered the war.

Now, there is growing discussion about furnishing Ukraine with another piece of Russian-origin technology -- the S-300 anti-aircraft system. This would be a big step up for Ukraine's defenders, because the missiles can hit planes at high altitude.

Slovakia says it is willing to provide the system it has in its arsenal to Ukraine, but only if NATO provides a replacement for its own defense.

One thing Biden won't be doing this week, the White House says, is making a risky, but hugely symbolic trip to Kyiv himself.

Polish Prime Minister Mateusz Morawiecki, along with the Czech and Slovenian prime ministers, traveled to the embattled capital last week. But "there are no plans to travel into Ukraine," Psaki said.