LISBON- Stricter COVID-19 rules will be imposed across the Lisbon region as authorities try to control a rise in infections that threatens Portugal's summer holiday season.

"We are in a fight against time between the progression of the disease and the process of vaccination," Cabinet Minister Mariana Vieira da Silva told a news conference on Thursday.

Portugal was still "far from its red lines but on the increase," she said.

From 3 p.m. on Friday until 6 a.m on Monday, people must present a negative coronavirus test or a vaccination certificate to leave or enter the Lisbon area. The tests must be PCR or antigen tests. Antigen tests are available for free in Lisbon pharmacies.

Restaurants, cafes and non-food shops across the region must close at 3.30 p.m. over the weekend. Supermarkets and grocery stores must close at 7 p.m..

The measures, prompted by a surge in coronavirus cases especially in and around the capital, are reviewed on a weekly basis but are likely to remain in place until the situation improves.

Coronavirus cases rose by 1,556 on Thursday, the biggest jump since late February, when the country of just over 10 million people was still under lockdown. In total, Portugal has recorded 869,879 cases and 17,079 deaths.

The jump in infections comes around a month after tourism-dependent Portugal opened to visitors from the European Union and Britain.

More than half of cases in Lisbon are of the more infectious Delta coronavirus variant, first identified in India but rapidly spreading in Britain.

"We would all like to have an end date for this situation, but we don't," Vieira da Silva said. "We need to respond early. The Delta variant has a large presence here."

Portugal is also speeding up the vaccination of younger people, with those aged 18 and above able to register from July 4. Around 30% of the population has been fully vaccinated so far.

(Reporting by Catarina Demony and Victoria Waldersee; Editing by Alison Williams) ((catarina.demony@thomsonreuters.com; +351 915 616 444 (Twitter: @CatarinaDemony);))