Extra police resources are needed in the wake of recent terror attacks, London's mayor and Met chief have said.
Sadiq Khan said the city had lost "thousands of police staff" since 2010 and Cressida Dick said she would "obviously" be seeking extra resources.
The call comes as another police chief and the Police Federation called for forces' resources across England to be boosted to fight terrorism.
Theresa May said the Met Police force was already "well resourced".
Seven people were killed near London Bridge when attackers drove into pedestrians and launched a knife attack.
Earlier on Monday, Jeremy Corbyn said Theresa May should pay a price in Thursday's general election for ignoring "repeated warnings" not to cut police numbers and agreed with those calling on her to resign in the wake of the London Bridge attacks.
However, the PM said she had protected counter-terror police numbers.
Mayor Mr Khan said earlier London received "half the funds we should be receiving - £170m versus £370m".
He added: "Over the next four years there are plans to cut a further £400m from our city's policing budget.
"There are plans to change the police funding formula which could mean we lose up to £700m on top of that, which leads to a total loss of our policing budget of £1.7bn and we don't receive the right level of funding as a capital city we should receive."
Ms Dick, asked whether she would demand additional officers, told ITV's Good Morning Britain she said forces had "become very much more efficient" and needed to "go on doing that in the future".
However, she added: "In the face of this changing and changed threat, absolutely I will be seeking for London and for policing generally more resourcing obviously."
Mrs May responded, saying the government had "protected counter-terrorism policing budgets" and "funded an uplift in the number of armed police officers."
Meanwhile, Devon and Cornwall Police's chief constable said police resources needed to be bolstered across the UK.
Chief Constable Shaun Sawyer said all policing areas from counter-terrorism to community policing needed more resources after Saturday's attack.
He tweeted: "Irrespective of politics, time to increase police resources in all corners of the UK."
On Sunday Mr Sawyer paid tribute to the work of officers who responded in London, writing: "More sadness. Thankfulness for the support of the public our heroic thin blue alongside other public services."
A senior firearms commander in the South West has also been critical of the current officer numbers following Saturday's attack.
Sgt Harry Tangye said on Twitter: "We the Police protested re cutting our numbers. We were ignored. You can't turn the police tap on instantly. We need to up the numbers now".
The police standards watchdog, Her Majesty's Inspectorate of Constabulary, found in March that some forces had "downgraded" 999 calls to help them cope with cuts.
How are forces coping with cuts?
The police standards report found:
- Three forces - Hertfordshire, Humberside and Nottinghamshire - had not been "responding appropriately" to emergency calls during inspections.
- If a force reclassified or downgraded a call because of a shortage of officers, it could then justify a slower response time, inspectors said.
- The Devon and Cornwall, Hampshire and Sussex forces had assessed domestic abuse victims over the phone rather than face to face.
- Other forces appeared to be avoiding classifying violent gangs as organised crime because doing so would stretch their resources.
The report concluded that most of England and Wales' 43 forces were providing a good service, however.
Officer numbers in Devon and Cornwall dropped from about 3,500 in 2010-11 to about 3,000 in 2016. The force was rated as "requires improvement" in the most recent HMIC inspection.
Calum Macleod, vice-chair of the Police Federation of England and Wales also joined calls for "more boots" which he said were "needed on the ground now" to "stop the terrorists before they claim more lives".
He said: "We're in danger of sleep-walking towards another tragedy if we don't recognise right now that community policing is on the critical list."
The Scottish Police Federation has said officers must not be "considered expendable" when dealing with terrorist attacks.