BARCELONA (Reuters) – A Spanish charity boat that rescues migrants at sea has been prevented by authorities from operating in the Mediterranean, a non-governmental organization said on Monday.

PHOTO FILE: The rescue boat of the NGO Proactiva Open Arms is moored with rescued migrants in the central Mediterranean Sea, at the Center for Temporary Assistance to Foreigners (CATE) of the port of Algeciras, Campamento, Spain, December 28, 2018. REUTERS / Jon Nazca / Photo File

The Barcelona Maritime Authority, in a letter to Reuters, said the Proactiva Open Arms charity had violated international agreements that rescued migrants should be transferred to the nearest port.

The minority Socialist Party government has accepted hundreds of migrants rescued by Open Arms this year, but anti-immigrant sentiment is on the rise in Spain, which has seen an increase in the number of people making this dangerous crossing by sea.

Open Arms, which operates in the waters between southern Europe and Libya, had already made it to Spain to land migrants after being denied leave of the to do in Italy and Malta.

"No action has been taken to have the landing as soon as possible. However, the boat had to wait with a large number of people on board and then crossed the Mediterranean for several days to arrive at a safe harbor, "reads the letter.

Open Arms will not be allowed to resume rescue operations "until an agreement is reached with the RS authorities concerned. [search and rescue] zones is in place, "the letter continues.

The Maritime Authority of Barcelona, ​​part of the Ministry of Public Works, could not be immediately contacted for comment.

Open Arms said Monday that he had appealed the decision.

"Preventing us from saving lives is irresponsible and cruel. The cowardly politicians have set the death meter on the move, "Open Arms founder Oscar Camps wrote on Twitter on Monday.

In November of last year, more than 600 African migrants had died trying to reach Spain since the beginning of the year, almost three times more than in 2017.

Illegal immigration by sea has decreased on average throughout Europe, although arrivals to Spain have more than doubled each year, reaching more than 1,000 people a week this year.

In December, Vox became the first anti-immigrant far-right party to be represented in a regional assembly in Spain since the end of the Franco dictatorship in the late 1970s.