British authorities are launching a criminal investigation into the London apartment building fire - as the death toll from the blaze has almost doubled, to 30.
Fire engulfed the social housing block, where as many as 600 people lived in more than 120 apartments.
"Sadly, at this time there are 58 people who we have been told were in the Grenfell Tower on the night that are missing".
Shortly after Saturday's meeting, Downing Street released a strongly-worded statement in which the Prime Minister said support in the immediate aftermath of the fire "was not good enough".
She faced cries of "coward" and "shame on you" as police restrained angry crowds, following accusations of avoiding local residents during a visit to the area Thursday.
Mr Khan, who said it was "humbling" to attend the service, paid tribute to the community for its resilience but said a feeling of anger remains.
"What I'm now absolutely focused on is ensuring that we get that support on the ground", Mrs May said in a BBC Newsnight interview.
There was a large police presence as Mrs May met a group of victims, residents, volunteers and community leaders at St Clement's Church close to the scene of the horrific blaze on Friday afternoon.
They demanded justice for the victims and claimed Wednesday's fatal blaze was due to negligence, with many citing the cladding that was put on the 1974 concrete tower during a recent refit.More news: Justin Thomas shoots 63, trails Brian Harman by 1 at US Open
But the PM, who had visited survivors in Chelsea and Westminster Hospital, dodged questions over whether she had failed to judge public mood.
There are 16 bodies now in a London morgue, Cundy said, and the remaining victims are missing and presumed dead. "But we need to make sure that that actually happens".
The cause of Wednesday's blaze in London is still under investigation, but anger has mounted in the community amid reports that exterior panelling used in an extensive renovation completed past year may have helped the flames to spread.
When asked about the biggest concerns of residents he said: "I think it comes down mainly to communication so it's the local people and those affected by this - it's unspeakable - it's ensuring they know the local authority is here, and local authorities through the entire city have come together, volunteers in their dozens are prepared to come out and do whatever they can". "It should define the leadership of May and she should be forced to resign", he said.
Cundy said emergency workers have now reached the top of the building. The inquest into the 2009 fire at Lakanal House in Camberwell, South London, in which six people died, took four years.
"The country has witnessed a succession of awful tragedies". She met survivors privately on Friday and promised measures including £5 million pounds (€5.7 million) for emergency costs, and new homes nearby within three weeks. "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".
Demonstrators from the Grenfell Tower area had gathered to protest the council's failure to act on warnings over fire safety in the building.
"The prime minister is distraught about what has happened", said Green, who was appointed May's deputy in the wake of the general election.
Protesters also called for Prime Minister Theresa May's resignation over the disaster, chanting "May must go" and "Justice for Greenfell", Ayoub added.