Spain respects Morocco's decision to restrict sea travel between the two countries during the summer as it was based on health criteria, the government spokeswoman said on Tuesday.

Between 3 million and 3.5 million Moroccans living in Europe usually make the crossing each summer, many of them through southern ports from Spain, and Spanish authorities take measures to help them.

The summer exodus did not happen last year because of restrictions imposed to curb the COVID-19 pandemic, and Morocco has said it would be the same this year.

"We are living a situation very similar to last year's, with even a higher incidence, and we all agree the more convenient was to suspend the 'Straits crossing' operation," spokeswoman Maria Jesus Montero told reporters.

The Moroccan foreign ministry announced on Sunday the country will reopen international passenger traffic through airports and ports for vaccinated people or those with a negative PCR test result.

However, Rabat decided to keep sea links with Spanish ports closed to passenger traffic.

Moroccans living in Europe will be able to cross via French and Italian ports instead, like last year.

Montero's comments came at a time of heightened diplomatic tension between the two countries. 

Spain said Morocco failed to control its borders and let thousands of migrants into its North African enclave of Ceuta.

Meanwhile, Morocco criticized Spain for admitting to hospital the leader of the Polisario Front, an organisation seeking the independence of Western Sahara, which is mostly under control of Morocco.

(Reporting by Inti Landauro, Emma Pinedo, Nathan Allen, Editing by Ingrid Melander and Angus MacSwan) ((;))