The security threat level in Britain is to remain at "critical" after a suspected plot to blow up ten passenger planes was thwarted on Thursday, Home Secretary John Reid said last night.
Mr Reid said he believed the 24 people being questioned were the main suspects but it was prudent to "err on the side of caution".
Everyone faced the threat and everyone "should respond with a common purpose and common solidarity", Mr Reid said.
Nineteen of 24 people arrested have had their UK assets frozen. The names have been published by the Bank of England.
There were reports that some of the suspects had substantial sums of money in their accounts, allegedly wired from Pakistan for the purchase of airline tickets.
The security operation continued today as further details emerged of the international investigation that led to the terror alert.
Two British men of Pakistani origin have been arrested by security forces in Pakistan in connection with the alleged plot. They were arrested in Lahore and Karachi last week.
According to the Pakistan Foreign Ministry there is indications of Afghanistan-based Al-Qaeda connection.
Mr Reid said the operation had a significant international dimension. He said he was "grateful" for the help of Pakistan, in particular. More than ever we need to draw on the tolerance and resilience of all parts of our community in the days ahead."
"This is a common threat to all of us and we should respond - all of us - with a common purpose and common solidarity."
"This is in the nature of the British people and that common solidarity and common cause is, I believe, now our most precious asset and we should foster it in all sections of our community."
Severe restrictions on what hand-baggage intending passengers can bring on a place will remain in place for the foreseeable future, it was confirmed.
The strict security checks are resulting in flights from UK airports are being delayed. Travellers are being warned to check with airlines before they set off.
One of those questioned was a woman from East London who taken into custody with her six-month-old baby. A pregnant woman was also taken into custody.
The oldest of the suspects named by the Bank of England is 35, and the youngest 17.
Thirteen are from east London - nine from Walthamstow, one from Chingford, one from Leyton, one from the Limehouse and Poplar area and one from Clapton.
Four are from High Wycombe, Buckinghamshire, and the other two are from Birmingham and Stoke Newington, north London.
Local reaction to the arrests was one of surprise, with many neighbours saying those detained were quiet, respectable people, some of whom had lived in the neighbourhood for many years.
All those arrested were British people of Pakistani decent or birth. Some 43 per cent of Britain's Muslim community are Pakistani.
There have been reports that two people held in Pakistan tipped off local police that an attack in Britain was imminent - which led to the British police making their move overnight on Thursday after months of surveillance.
Intelligence agents in Pakistan had arrested at least seven people, including two British nationals of Pakistani origin, who provided information on the alleged plot to blow up US-bound passenger jets from Britain.
Mr Reid's belief that the main suspects have been detained differs from that US authorities who said earlier today there may be as many as five plotters still at large and claimed the plotters had been infiltrated by a British agent - which led to the operation.