ROME — French government spokeswoman Sibeth Ndiaye said on Tuesday that the behavior of Italian interior minister Matteo Salvini on migration issues was “unacceptable” in reference to the recent confrontation with the Sea-Watch NGO.

“I think the Italian government has not been up to the standards it should be,” said Ms. Ndiaye in an interview on French television Tuesday morning. “The behavior of Mr. Matteo Salvini on the migration issue is unacceptable.”

The French spokeswoman’s words followed a major stand-off between the Italian populist government and the German NGO Sea-Watch, which illegally docked at Lampedusa last weekend to unload the 42 African migrants it was carrying.

Italian police subsequently impounded the NGO vessel and arrested the ship’s captain, the 31-year-old activist Carola Rackete.

In her interview, Ms. Ndiaye said that Mr. Salvini has been employing a “strategy of hysterization, which consists of blowing out of proportion a subject that is a painful subject, a complex subject, and over which the European Union and France have been in solidarity with Italy.”

The French spokeswoman said that rules had been established at the level of the European Union (EU) and that these rules had been accepted by Italy.

“These maritime laws tell us that when there are people who are in distress on the sea, they must be deposited in the nearest safe harbor, and in this case they are Italian ports,” she said.

She added, however, that non-governmental organizations (NGOs) that come to the rescue of migrants attempting to cross the Mediterranean should also “be cautious in the way they act.”

Mr. Salvini, who also heads Italy’s most powerful political party, the Lega, responded immediately to the French spokeswoman, urging France to open in own ports to migrants if it feels so strongly about it.

“My behavior on immigration is unacceptable?” Salvini tweeted. “The French government should stop insulting and open its ports, since the Italians have already welcomed (and spent) too much.”

“The next boats? Destination Marseille,” he concluded, in reference to France’s southernmost port city.

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