WASHINGTON (AFP, REUTERS) - As United States President Donald Trump orders American troops out of Germany and faces a tough re-election battle, his top diplomat is heading to friendly climes in Central and Eastern Europe.

Secretary of State Mike Pompeo opens a five-day trip on Tuesday (Aug 11) that will terminate in close ally Poland, which is eager to welcome some of the US troops leaving Germany to guard against historic adversary Russia.

He will also travel to the Czech Republic, Slovenia and Austria where he is expected to press his campaign for nations to shun Huawei, the Chinese telecoms giant considered a threat by Washington as it takes a lead in fifth-generation Internet.

On Thursday in Slovenia, where he will be the first US secretary of state to visit since 2001, Mr Pompeo will sign an agreement on 5G, officials said without previewing details.

Mr Pompeo's trip comes weeks after the Pentagon said the US would bring home some 6,400 military personnel from Germany and shift nearly 5,600 more to other Nato allies including Italy and Belgium.

Mr Trump has a tense relationship with German Chancellor Angela Merkel, who declined his invitation for a Group of Seven summit in Washington in the middle of the coronavirus pandemic, and accuses Europe's largest economy of unfair trading practices.

"What is most significant about this trip is the places the secretary is not going to," said Mr Ian Lesser, the Brussels-based vice-president of the German Marshall Fund of the US.

"If the secretary was going to address the core issues in transatlantic relations at the moment, he would be making stops in Brussels, Paris and Berlin."

Mr Lesser said that the troop repositioning out of Germany was unlikely to be a major issue for US voters.

"What does have some political resonance is how a senior American official is received when he or she goes to Europe," he said.

"This is a low-risk visit from the point of view of the administration," he said. "They want to give an impression of foreign policy success."

Mr Pompeo last month visited Britain and Denmark and also travelled last year to Poland, where President Andrzej Duda has formed close relations with Mr Trump.

Mr Trump invited Mr Duda to the White House days before Poland's election in June, in which Mr Duda won a narrow victory after a polarising campaign in which he attacked LGBT rights.

Polish Defence Minister Mariusz Blaszczak has said that the US will deploy at least 1,000 additional troops to Poland.

"I think it's fair to say Poland is one of our closest and strongest allies. We enjoy unprecedented levels of bilateral relations," Mr Phil Reeker, the top State Department official for Europe, told reporters.

He pointed out that Poland is one of the few Nato nations to meet a goal of spending 2 per cent of gross domestic product on defence - unlike Germany, in a running sore point for the Trump administration.

Mr Reeker said that Mr Pompeo will also raise energy independence from Russia.

Mr Pompeo last month opened the way for sanctions over the Nord Stream 2 pipeline being built from Russia to Germany.

Poland adamantly opposes the project, fearing it strengthens Russia's influence over Europe, while an Austrian company is among the participants.

The tour will be heavy on historical symbolism. In the Czech Republic, Mr Pompeo will head to Pilsen to mark western Bohemia's 1945 liberation by US troops under George Patton.

But at least one of Mr Pompeo's meetings may be tense. Czech President Milos Zeman is known for his outspoken remarks including support of Russia and China.

Mr Reeker said Mr Pompeo would have a "short discussion" with Mr Zeman during what he called a courtesy call.

Besides Germany, the US also plans to cut its troop levels in Afghanistan to "a number less than 5,000" by the end of November, Defence Secretary Mark Esper said in an interview broadcast with Fox News on Saturday, adding detail to drawdown plans that Mr Trump had announced earlier this week. The US currently has about 8,600 troops in Afghanistan.

Mr Trump said in an interview released last Monday by Axios that the US planned to lower that number to about 4,000.