The government will fully fund the costs of dealing with the Manchester Arena attack, Prime Minister Theresa May has said.
It comes after Greater Manchester mayor Andy Burnham said an initial offer was "not good enough".
But the PM told the Manchester Evening News: "Be in no doubt, Manchester will get the financial support it needs."
She added in a statement that a Cabinet Office taskforce had been set up to oversee meeting the costs.
Suicide bomber Salman Abedi detonated a device that killed 22 people and injured 512 in the foyer of the venue at an Ariana Grande concert on 22 May.
The government had previously said Manchester would receive £12m to help cover the "exceptional costs" of the attack, with £3m being made available immediately.
But Mr Burnham said more than £17.5m had already been spent and suggested at least £10.4m more could be needed, including for the inquests into the 22 deaths and an inquiry.
The £12m figure would have meant local authorities being forced to cut services to make up the £5m shortfall on what had already been spent, he warned.
Mrs May told the Manchester Evening News: "Be in no doubt, Manchester will get the financial support it needs – and if that costs £28m, as Andy Burnham has estimated, then that is what we will make available."
She added in a statement that the attack was "one of the darkest moments in the city's history".
"I promised in the wake of that appalling atrocity this government would do all it could to help victims recover and the city to heal. I repeat that commitment today," she said.
"Where your public services have had to bear, or will bear, unexpected and exceptional costs in coping with this terrible attack, these will be met by the government.
"The process of making those payments is ongoing and I understand the frustration felt at the pace of delivery.
"So I have taken steps to speed up our response. Over the weekend a taskforce has been established within the Cabinet Office to oversee progress and expedite payments when necessary."
Mrs May added that not all the funding would be needed immediately.
"For example the inquests, opened and adjourned this month, will not begin until next June," she said.