Thousands of people have attended a vigil in Trafalgar Square, London, to remember the bombing victims and thank emergency crews for their efforts.
Mayor Ken Livingstone said emergency services had been "magnificent" and he praised Londoners' "calm and courage".
Lord Coe said efforts towards organising the 2012 Olympics in London would be dedicated to the victims.
A man injured in last Thursday's bus bombing has died in hospital, taking the overall attacks death toll to 54.
Police say three of the four bombers thought to have died in the attacks are included in this figure.
Scotland Yard said on Thursday a man had died in the National Hospital for Neurology, in Queen Square, London, where he had been taken following the bombing on the Number 30 bus in Tavistock Square.
Earlier on Thursday, people around the UK and the world took part in a two-minute silence to remember those killed and injured a week ago.
Civil rights campaigner Ben Okri told the crowds in Trafalgar Square that London had survived "bombings, burnings and wars" and still grown stronger and more beautiful.
Mr Livingstone told those assembled he was "proud" to be their mayor.
"And out of this tragedy, let us re-double our efforts to build a better city for our children and our grandchildren and lift our hearts, rather than worry about who to blame or who to hate," he said.
Lord Coe, chairman of London's successful 2012 Olympic bid team, said the victims would never be forgotten as London prepared to host the Games.
"As we move forward we will never forget those who suffered so grievously last Thursday, but our efforts and actions over the next seven years are dedicated to them," he said.
Metropolitan Police Commander Bob Broadhurst also paid tribute to the emergency services, adding that these workers saw things they should never have to see in a city like London.
Nick Collins, from London Fire Brigade, told those gathered he had been in command of firefighters at the King's Cross site.
"We're really proud of the way our firefighters responded and will continue to be so," he said.
Chief Rabbi Sir Jonathan Sacks was also among the speakers. He described London as the "city of courage".
"It has the courage not to give terror the victory of making us angry and in our anger lose the values that make us what we are. Let that courage unite us now," he said.
Londoners listened to speeches and readings
The Bishop of London, the Right Reverend Richard Chartres, said those who had died, as well as the injured and suffering, were of all faiths but all Londoners.
The secretary general of the Muslim Council of Britain, Sir Iqbal Sacranie, referred to the words of the Prophet Mohammed, which, he said, were the true words of Islam.
He also made an appeal for divisions to be avoided as a result of last week's attacks.
General Secretary of the TUC, Brendan Barber, Director of Liberty Shami Chakrabati, ITV news anchor Sir Trevor Macdonald and comedian Jo Brand were among the other speakers.