Authorities in London said Saturday that 58 people are missing and presumed dead from this week's fire disaster at a London high-rise tower.

The update from police came as Prime Minster Theresa May met for more than two hours with survivors of the high-rise fire at her office at 10 Downing Street. May has faced a barrage of criticism for the government's initial response to the tragedy that authorities had initially said left at least 30 dead.

"The figure of 58 are those who are missing and that we have to presume are dead," said Commander Stuart Cundy, a spokesman for London's Metropolitan Police. "It might be that some of those are safe and well but for whatever reason have not reached (out) to let us know. Again, I would urge them if that is you, I don't care the reason, please, please contact us."

Cundy added that it will take weeks or longer to recover and identify all the dead in the public housing block that was devastated by a fire early Wednesday. He also cautioned there may have been people in the tower that police are not aware of, which would add to the death toll.

The search of the 24-floor building had been paused on Friday due to safety concerns, but has now resumed, Cundy said.

"My heart goes out to those affected,” Cundy said. "As soon as we can, we will locate and recover loved ones."

Hundreds of angry protesters gathered outside 10 Downing Street on Saturday, raising chants that called May a "coward, British news outlets reported. Protesters are demanding to know why long-standing fire safety concerns raised by a tenants' group about the public housing tower, tucked in the city's ritzy North Kensington neighborhood, had not been addressed. They also expressed anger that the prime minister did not meet with survivors or victims of the fire when she initially visited the neighborhood following the tragedy.

“She’s a coward and needs to leave," Tilly Howard, a protester told the Guardian newspaper. "The people are waking up to the right wing mainstream media and May just doesn’t get the public mood.”

Earlier on Saturday, Queen Elizabeth II and her husband Prince Philip observed a minute of silence to honor the victims of the London high-rise fire. They paid their respect before the start of the annual Trooping the Color procession that marks the observance of the Queen's birthday.

The Queen said in a statement that she was "profoundly struck by the immediate inclination of people throughout the country to offer comfort and support to those in desperate need."

"Put to the test, the United Kingdom has been resolute in the face of adversity," she added. "United in our sadness, we are equally determined, without fear or favor, to support all those rebuilding lives so horribly affected by injury and loss."