"We look forward to working with President-elect @JoeBiden to further strengthen ties between the #UnitedStates & #Europe, as we face global challenges none of us can tackle alone," NATO's Jens Stoltenberg wrote on Twitter after meeting European Council President Charles Michel.

EU foreign policy chief Josep Borrell also took part in the working dinner on the eve of Biden's swearing in.

Traditional US allies in the European Union and NATO were often shunned by outgoing US President Donald Trump throughout his divisive four years in office.

Biden has signalled he intends to repair those relationships and return to multilateralism, underscored by his nomination of seasoned diplomat Antony Blinken for secretary of state.

Stoltenberg has invited Biden to participate in a NATO summit at a date to be set, while Michel has proposed organising a special meeting with the incoming president and EU leaders.