With an influx of British tourists on the horizon, Spain tightens entry requirements.

Prime Minister Pedro Sánchez of Spain announced on Monday that British visitors would have to present a negative Covid-19 test or proof of full vaccination, bowing to concerns about a massive influx of summer tourists from Britain, which has been grappling with the Delta variant of the disease.

Last week, the British government added Spain’s Balearic Islands to its “green list” of countries and territories from which British visitors can return without quarantining, providing a major lift to the islands’ tourism-dependent economies.

But the authorities on the islands then asked Spain’s central government for tougher screening measures for arrivals from Britain. Sensitivities were also raised after an outbreak among hundreds of Spanish students who were visiting Mallorca, the largest of the islands, to celebrate the end of their academic year.

Spain lifted restrictions on British visitors on May 24, just as Germany, France and some other European countries reintroduced quarantine rules for the British in order to avoid the spread of the Delta variant. Since then, Germany and France have pushed for a British quarantine obligation to be applied across the European Union, but so far to no avail, as countries like Spain rely heavily on British visitors in the summer tourism season.

In other news from around the world:

• Italy said on Monday that people were no longer required to wear masks outside, joining Spain and France in relaxing the rules as cases dropped. Masks must still be worn indoors and in crowded areas. In Rome, many still wore masks on Monday, citing concerns about the Delta variant, but some took advantage of the new rules. “It feels like freedom,” said Francesca Tronconi, a tour guide, as she crossed Piazza Navona with her mask around her arm.

• Young people in Greece will be offered an incentive to get vaccinated, Prime Minister Kyriakos Mitsotakis said on Monday, in the form of a “freedom pass” of 150 euros, about $180, in prepaid credit to be spent on tourism, culture and travel. The pass will be available from July 15 for people ages 18 to 25 who have had at least one shot. “It is a thank you to youngsters for their patience and persistence and an incentive to get inoculated,” Mr. Mitsotakis said.

• All passenger flights from Britain to Hong Kong will be banned starting Thursday to prevent the spread of the Delta variant, the city’s government said in a statement on Monday. The authorities have added Britain to an “extremely high-risk” list.