(From left) President of the EU Commission Ursula von der Leyen, US President Joe Biden and European Council President Charles Michel arrive for the EU-US summit at the European Union headquarters in Brussels on Tuesday. Photo: AFP

Uncertainties and problems are still looming in transatlantic relations even after US President Joe Biden made a two-hour stopover Tuesday at EU headquarters signaling that it is in the US interest to maintain a friendly relationship with Europe.

In Brussels' iconic Europa Building - the seat of the European Council and Council of the European Union, Biden reiterated his slogan that "America is back," saying "the world has changed" during his meeting with European Commission President Ursula von der Leyen and President of the European Council Charles Michel.

"It's overwhelmingly in the interest of the USA to have a great relationship with NATO and the EU. I have very different views than my predecessor," Biden said, hinting that he will overturn the policies imposed on Europe by former US President Donald Trump.

Despite optimistic echoes from some EU officials, observers are still worried that US diplomacy is not stable again for good as it is noted that Trump's policies and his influence on the Republicans are hardly vanishing.

"A lot of Europeans will be very cautious when it comes to this renewal of transatlantic relations, because what they have experienced," Julian Mueller-Kaler, a researcher with the Berlin-based German Council on Foreign Relations, told Xinhua in an interview.

Mueller-Kaler said Biden's primary goal is to assure America's traditional partners that "the country is not leaving, hanging nor abandoning its role in international politics."

One tangible result of Tuesday's meeting was a breakthrough in the long-running dispute over subsidies for aircraft manufacturers Boeing and Airbus.

Officials from both sides confirmed that the tariffs as part of the trade war imposed during the Trump administration will be officially suspended on July 11.

The US reserved its rights to reimplement the tariffs if Washington finds that American companies are not able to "compete fairly" with their EU counterparts, according to US Trade Representative Katherine Tai.

The truce was seen as a first good-will gesture by Biden's government to reverse the trade policies against the EU.

Unsolved rows include the tariff on steel and aluminium that Trump slapped on Europe and other close partners in 2018. But the US authorities have been reluctant to give them up easily as the upholders of the trade barrier are still politically lucrative for Biden.

Von der Leyen said Brussels has set up a working group to further discuss the "difficult fields" and hopes the tariff will come to an end by December.