President Donald Trump says the US will send an extra 5,000 troops to Poland, a week after the Pentagon cancelled a planned deployment of 4,000 troops to the country.
Writing on his Truth Social platform on Thursday, Trump said the decision was based on the US's relationship with Polish President Karol Nawrocki, whom he backed during presidential elections last year and who is a long-time supporter of his.
Trump did not elaborate on whether the additional troops were part of the previous planned deployment or a different operation.
The Nato Secretary General welcomed the move ahead of a meeting of foreign ministers in Sweden.
Mark Rutte told reporters the trajectory towards Europe becoming less reliant on the US "will continue".
Polish Prime Minister Donald Tusk called the announcement "good news" for both countries, adding in a post on X: "I thank all those involved in this matter—President Nawrocki, the ministers, congressmen, and friends of Poland in the USA—for their effectiveness and unity of action."
The defence department abruptly said last week it was cancelling the deployment of 4,000 troops to Poland, but US Defence Secretary Pete Hegseth later said it was "a temporary delay" and Washington would continue to ensure it "retains a strong military presence" in the country.
The White House has also signalled in recent weeks that it intends to reduce its overall troop levels in Europe as part of its "America First" agenda.
Rubio is expected to call for increased burden sharing from Washington's Nato partners at Friday's talks in Helsingborg.
Speaking to reporters ahead of them, he said: "The president's views are frankly disappointment at some of our Nato allies and their response to our operations in the Middle East.
"In the meantime there are other areas where we continue with cooperation," he added - citing the Poland announcement.
"That said, obviously the United States continues to have global commitments that it needs to meet in terms of our force deployment and that constantly requires us to re-examine where we put troops - this is not a punitive thing."
Earlier, the BBC asked Rubio about unconfirmed reports the US could shrink its total troop numbers available in the event of an attack on a Nato country.
He said "some of those issues" would be discussed at the summit, adding Trump remained very upset and disappointed with Nato allies.
German Foreign Minister Johann Wadephul has also welcomed the US decision to deploy additional troops to Poland, telling reporters: "It serves not only for Poland's security, but for the security of the whole alliance and so also for us. So, this is absolutely in our interest".
Earlier this month, the US announced it would withdraw 5,000 troops from Germany after a row between Trump and German Chancellor Friedrich Merz over the war with Iran.
It is unclear whether the additional troops for Poland were part of those withdrawing from Germany or a separate group.
Wadephul added on Friday that Germany was in "ongoing discussions" with the US about deploying long range missile systems in Germany.
"We are inviting the United States of America to stay to their previous plans," he added.
Several Republican lawmakers in the US have criticised Trump's decision to withdraw troops from Germany, saying it risked sending the wrong message to Russia.
The US military deployment in Germany is by far its biggest in Europe. Currently more than 36,000 troops are on active duty there compared to about 12,000 troops in Italy and 10,000 in the UK.
Trump previously criticised Merz over his suggestion the US had been "humiliated" by Iran during negotiations to end the conflict in the Middle East. The US president has also been critical of Nato allies for their unwillingness to join him in pressuring Iran over the Strait of Hormuz.
Rubio said on Friday there had been "slight progress" in negotiations on Iran, but did not expand with any details.
"We await word on those conversations that are ongoing [...] I don't want to exaggerate it, but there's been a little bit of movement," he said.
