BRUSSELS: European Union leaders will urge Britain to respect the rights of their citizens, according to a draft of the statement they will agree at a summit next week, a reference to concerns about the handling of EU nationals by British immigration authorities.

"The European Council calls on the UK to respect the principle of non-discrimination among member states and the rights of EU citizens," said the draft, a copy of which was seen by Reuters.

The comments come amid concern about reports that European Union citizens have been detained, some for several days, at immigration centres in Britain due to the end of freedom of movement following the U.K.'s exit from the bloc.

Dacian Ciolos, president of the European Parliament's main liberal group, wrote to the European Commission last week to raise concerns about detention measures that were "clearly disproportionate" and "serious impediments" to relations between the EU and Britain.