The Italian foreign ministry summoned France’s ambassador on Saturday, after uniformed French customs officers crossed the border to confront a man suspected of carrying drugs.

France insisted the presence of its personnel at an alpine railway station just inside Italy was acceptable.

However, the French ambassador, Christian Masset, was summoned over what Rome called “a serious act considered outside the scope of cooperation between states sharing a border”.

The foreign ministry added that the neighbouring countries would address the issue further at a meeting in Turin on 16 April.

The dispute began late on Friday when the French officials turned up at a train station in the Italian alpine village of Bardonecchia and told a man to provide a urine sample. The Rainbow4Africa NGO, which has for months occupied part of the train station to help migrants headed for France, filed a complaint about the treatement of the man, who is from Nigeria.

Italian officials reacted with outrage, prompting an official explanatory statement from the French embassy.

Gerald Darmanin, the French minister charged with overseeing customs, signed the statement which explained how French officials came to be present when the Paris-bound train arrived from Milan.

“These uniformed agents identified as French customs officials suspected one passenger, a Nigerian national resident in Italy, of having drugs on his person.

“In line with article 60 bis of the customs code the agents asked the person if he would consent to providing a urine sample to detect drugs which he agreed to do in writing,” the statement read.

“In order to carry out the test in conditions respecting the person, the agents waited until the train arrived to use the facility at Bardonecchia station which was placed at the disposal of French customs,” the statement went on, saying the procedure respected guidelines laid down in 1990.

The French officials duly carried out the test which came back negative.

But the Italian foreign ministry said France had failed to keep them fully abreast of developments, and criticised the incident as “unacceptable”.

Matteo Salvini, the head of Italy’s far-right League, commented that Rome, “instead of expelling Russian diplomats should remove French diplomats”, referring to the furore over the poisoning of a former Russian spy in Britain, widely blamed on Moscow.