Republican US Senator Lindsey Graham and Democratic Senator Chris Van Hollen called on the Trump administration on Monday to impose sanctions on Turkey over its purchase of the Russian system, saying the failure to do so sends a "terrible signal" to other countries.
Polish President Andrzej Duda held a telephone conversation with his Turkish counterpart, Recep Tayyip Erdogan, on Monday to discuss Turkey's support for North Atlantic Treaty Organisation plans for the Baltic region, before flying to London for a North Atlantic Treaty Organisation summit, Duda's chief aide has said.
"He's two-faced", Trump said of Trudeau during a brief news conference alongside German Chancellor Angela Merkel on Wednesday.
"The message to Turkey.is we need to move forward on these response plans and it can't be held up by their own particular concerns", Esper said as he flew to London. That border is a mess for a long time. "We pulled our soldiers out and took over the oil", Trump mentioned. And that's what they're doing. We discussed numerous things, and we're getting along very well. So we're very happy.
"The presidents discussed the importance of Turkey fulfilling its alliance commitments, further strengthening commerce through boosting bilateral trade by $100 billion, regional security challenges, and energy security", the White House said. "It's a very unsafe statement for them to make".
After meetings between Erdogan and US President Donald Trump, as well as Baltic and Polish leaders, Turkey dropped its objections, but the fractious mood continued even after the summit ended.
In the runup to Turkey's S-400 purchase, the USA used the threat of withholding the next-generation F-35 stealth fighter jet from Ankara as a bargaining chip, citing concerns that the S-400 could learn the jet's "secrets" if operated alongside it.
Washington and Paris have long argued over NATO's goal - France opposed the 2003 Iraq war - but the new tensions will add to doubts over the alliance's future that have grown with Trump's ambivalence over US commitments to defend Europe.