Hundreds have attended a service at Southwark Cathedral for two people killed in the London Bridge attack.
The Dean of Southwark Cathedral, the Very Revd Andrew Nunn, said many people were struggling with what happened.
He described the latest attack as “déjà vu” after eight people were killed in a terror attack nearby in June 2017.
On Friday, Southwark Cathedral was put into lockdown as people ran away from London Bridge – where Khan was wrestled to the ground by members of the public and later shot dead by police.
As crowds ran towards the cathedral, Mr Nunn said he “wondered what an earth was going on”, adding that it brought back memories of the earlier attack two years ago, which left eight dead and 48 injured.
He described “that sense of déjà vu, and then realising that déjà vu passes very quickly and this, in fact, was reality again”.
“I think what it revealed to me is that the second time around can really, really hurt – so I think that’s what people are finding at the moment.”
Speaking at the service, Mr Nunn said “memories have been stirred and wounds have been re-opened”.
He added: “What seemed to have been put to the back of people’s minds has now been brought to the fore.
“There will be people around here who will feel fearful, people who would perhaps be anywhere other than here.
“Others who just want life to be normal. We have to stand with them. We have to help bear their pain but also speak to that pain with words of hope.”
Mr Nunn praised the bravery of the people who confronted Khan as he carried out his attack.
“The actions of evil people can have a terrible impact on our lives,” he added. “But these people are few in number compared to the good people we see all around us
“Every event of this nature produces stories of such selfless acts of bravery.”
London Bridge remains cordoned off while forensic officers continue to search the scene where Khan carried out his attack and was killed.
Khan, 28, a convicted terrorist, launched the attack inside Fishmongers’ Hall, where he was one of dozens of students and offenders attending a conference on prisoner rehabilitation.
The attack then continued onto London Bridge itself.
Three injured people remain in hospital. Two are in a stable condition and the third person has less serious injuries.
This latest attack comes after the UK’s terrorism threat level was downgraded on 4 November from “severe” to “substantial”, meaning that attacks were thought to be “likely” rather than “highly likely”.
The terror threat level is reviewed every six months by the Joint Terrorism Analysis Centre, which makes recommendations independent of government.