US Secretary of State John Kerry was heading to Poland Monday for talks on growing trade ties, as well as plans to base an American missile defence system there in 2018.
His visit also comes against a background of European anger over the revelations of the extent of the US spying programme, which have triggered a rift in trans-Atlantic ties. Kerry acknowledged last week for the first time that in some cases US spying has gone too far.
"I assure you, innocent people are not being abused in this process, but there's an effort to try to gather information," Kerry told a London conference via video link. "And yes, in some cases, it has reached too far inappropriately."
The top US diplomat was to fly in from Saudi Arabia late Monday, and head straight to a wreath laying in memory of Tadeusz Mazowiecki, the first non-Communist premier in Soviet-dominated eastern Europe, who died a week ago aged 86.
US officials highlighted that Washington has major economic and defence ties with the central European powerhouse.
A US missile defence plan for Europe -- to counter a potential Iran threat -- envisages deploying dozens of SM-3 interceptors in Romania and Poland between now and 2018.
"Poland is an important part of the European Phased Adaptive Approach to the NATO missile defence, and we will deploy a missile defence site in Poland in the 2018 time frame," State Department spokeswoman Jen Psaki said last week.
She also stressed that "Poland is the largest commercial partner of the United States in Central Europe, and the United States is one of the top sources of foreign investment in Poland. So that's an incredibly important economic relationship."
Psaki said bilateral trade has quadrupled in the past 10 years, and US exports to Poland "grew over 37 percent just in the first seven months of 2013."
American businesses have also invested some $20 billion in Poland and employ directly some 180,000 staff.
Online US giant Amazon announced last month it would open three logistics hubs in Poland by 2015, creating some 6,000 new jobs.
Kerry, who is on an 11-day tour mostly through the Middle East and North Africa, will meet Tuesday with Prime Minister Donald Tusk and Foreign Minister Radoslaw Sikorski, and hold a round table with Polish innovators some of whom are working directly with Silicon Valley companies.
The spying row has spurred tensions surrounding talks to create Transatlantic Trade and Investment Partnership (TTIP) aimed at establishing the world's largest free-trade zone.
Kerry is likely to address the concerns when he meets later Tuesday with American and Polish businesses at a lunch organised by the American Chamber of Commerce.
He will then head to a Polish Air Force base in central Lask to meet US and Polish pilots who have been doing joint training since November 2012.
It "represents the first-ever continuous presence of US troops in Poland," Psaki said.
"Polish forces are also making key contributions as part of the ISAF mission in Afghanistan with approximately 1,100 Polish troops serving side by side with us there," she added.