US president Joe Biden will on Wednesday arrive in Brussels for talks with key western leaders amid concerns that the conflict in Ukraine could intensify and where differences have emerged in recent weeks over the provision of more offensive weapons to Kyiv.
Biden has skilfully drawn together a strong, united group of nations who have imposed punitive sanctions on Russia over its aggression in Ukraine without the internal squabbling and dithering that many observers had anticipated would take place.
The US president said on Monday that Nato had "never been stronger or more united in its entire history", largely due to miscalculations by Russian leader Vladimir Putin in deciding to invade Ukraine.
However with the war now under way for almost a month and showing no immediate prospect of relenting, there are concerns about what will happen next and what the alliance should do to further support the Ukrainians.
On Monday, Biden told business leaders in Washington that “Putin’s back is against the wall”.
“He wasn’t anticipating the extent or the strength of our unity. And the more his back is against the wall, the greater the severity of the tactics he may employ.”
Biden said Putin was considering using chemical or biological weapons. "We've seen it before. He's run a lot of false-flag operations. Whenever he starts talking about something he thinks Nato, Ukraine, or the United States is about to do, it means he's getting ready to do it. Not a joke.
"And he's – now he's talking about new false flags he's setting up, including he's asserting that, we, in America, have biological as well as chemical weapons in Europe – simply not true. I guarantee you.
“They’re also suggesting that Ukraine has biological and chemical weapons in Ukraine. That’s a clear sign he is considering using both of those. He’s already used chemical weapons in the past, and we should be careful of . . . what’s about to come. He knows there’ll be severe consequences because of the united Nato front, but the point is: it’s real.”
Earlier on Monday, the White House at a press briefing also warned that "based on evolving threat intelligence . . . the Russian government is exploring options for potential cyberattacks on critical infrastructure in the United States".
The White House wasn’t making specific predictions but rather just urging business to be careful. However, the warning was clear.
Biden and his officials are also likely to discuss with western leaders the US concerns that China may provide financial or military support to Russia.
US strategists maintain that the war in Ukraine is not going well for Russia and that it has experienced significant losses of both personnel and equipment. The Americans contend that Russia has reached out to the Chinese for backing.
Last week the White House said, following a lengthy phone conversation between Biden and Chinese leader Xi Jinping , that there would be “implications and consequences” if China provided material support to Russia.
After meeting with Nato and European leaders, Biden will travel on to Poland, which faces significant pressures from the refugee crisis generated by the Russian attack on Ukraine.
Biden may visit a camp for refugees on his trip this week and promise American support. However, the White House has downplayed any prospect of the president travelling into Ukraine as some eastern European leaders did last week.
It is with Poland that the US has had its public disagreement over strategy regarding Ukraine. The US turned down an offer by Poland to deliver MiG-29 fighter jets in its possession to an American military base for use in Ukraine.
Ukrainian president Volodymyr Zelensky had sought the aircraft. However, the Biden administration was concerned that Poland's offer could increase tensions with Russia.
US military chiefs have reportedly briefed Congress that the main issue was that the Mig-29s could threaten Russia itself and lead to the Kremlin hitting out at a Nato country.
Another interesting feature of the Nato summit will be whether the US raises the issue of a sophisticated air defence system, known as the S-400, bought by Turkey from Russia several years ago.
At the time the US was furious and Turkey was dropped from the programme to re-equip its air force with very modern American F-35 jets. American officials have in recent weeks floated the idea that the S-400 anti-aircraft system could be provided by Turkey to Ukraine – potentially a way of ending the dispute over access to the F-35 aircraft.