WARSAW — If Russian President Vladimir V. Putin had been to order tanks into different European nations, the 9 nations alongside NATO’s jap flank can be the likeliest targets.

So on Wednesday, President Biden will meet with the leaders of these nations, providing reassurance that america is ready to defend probably the most weak members of the alliance from the type of assault now going down in Ukraine.

The assembly, slated to happen simply hours earlier than Mr. Biden concludes his three-day go to to Ukraine and Poland, is supposed to underscore his administration’s dedication to confront Mr. Putin and forestall him from intimidating a number of the world’s extra fragile democracies.

“These are largely the group of jap flank NATO allies who’re principally and, fairly frankly, actually on the entrance traces of our collective protection proper now,” John Kirby, a senior spokesman for the Nationwide Safety Council, informed reporters earlier than the president’s journey.

Mr. Kirby mentioned the president would meet with leaders of the 9 nations — Bulgaria, the Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, Romania and Slovakia — to “reaffirm america’ unwavering assist for the safety of that alliance and trans-Atlantic unity.”

In his speech from the royal citadel in Warsaw on Tuesday, Mr. Biden was firm in regards to the American dedication to the protection of all of NATO, declaring that the assure to come back to assistance from any threatened ally “is rock strong. And each member of NATO is aware of it. And Russia is aware of it as effectively.”

However the specter of direct army intervention is much less theoretical for Poland, Hungary and the opposite nations whose borders lie not removed from Russian territory than for Britain, France or Spain.

For these nations, Mr. Putin’s invasion of Ukraine nearly a yr in the past is just not solely a menace to the precept of democracy, but in addition a highway map for an invasion that would simply as rapidly plunge their very own cities into the darkness of warfare.

Recognizing that particular menace, the leaders of the 9 nations got here collectively in 2015 to debate the steps they might take to scale back the chance. The gathering on Wednesday with the American president would be the most high-profile, and pressing, assembly for the reason that group was fashioned eight years in the past.

For Mr. Biden, it is going to be one other alternative to reward NATO’s unity within the face of Mr. Putin’s actions. In his briefing final week, Mr. Kirby mentioned that the group would deal with sustaining a unity of goal even because the warfare in Ukraine drags on.

White Home officers mentioned america and its allies would quickly announce more durable sanctions on Russia geared toward growing the price of Mr. Putin’s warfare.

“The leaders will talk about our efforts over the previous yr to strengthen NATO, which is stronger and now extra united than it was — than it has ever been, and the way every of our nations will proceed to work collectively,” he mentioned.

After the assembly, Mr. Biden is anticipated to depart Poland and return to Washington, concluding a international journey that started together with his top-secret go to to Ukraine’s capital.