The central government will make 2,000 soldiers who are trained in tracking available to the regions, which are responsible for health care, to assist in tracking cases and stem a rise in infections, he told a news conference.

"We could even increase this figure as required through the urgent training which we have planned," Sanchez said.

Many experts have blamed a lack of virus trackers for a surge in COVID-19 infections in several Spanish regions such as Madrid and Catalonia.

Sanchez urged Spaniards to use a smartphone app designed by the government called RadarCovid which can identify people who have crossed paths with a contagious patient and alert them so they can get tested or be quarantined.

He also announced that regional authorities could ask the central government to apply a state of emergency, which would allow it to limit people's movements, on part or all of its territory.

The central government declared a nationwide state of emergency in mid-March which allowed it to impose one of the world's strictest lockdowns, with people allowed outside only to buy food or medicine, seek medical care, briefly walk their dog or go to work if it was impossible to do their jobs from home. It was only fully lifted on June 21.

While the rise in infections in Spain is "worrying", it is "far from the situation in mid-March", Sanchez said.

"We can't let the pandemic to once again take control of our lives... we must take control and halt this second curve."

Infections have risen sharply since Spain lifted the lockdown, but deaths have been much lower than during the epidemic's peak.

The country has more than 400,000 confirmed cases of the respiratory disease, the highest in western Europe, and one of the fastest growth rates on the continent.

Nearly 29,000 people have died, one of the world's highest tolls.