All six were arrested on suspicion of the commission, preparation or instigation of terrorist acts and detained under Section 41 of the Terrorism Act 2000.
Warrants of further detention, for up to seven more days, were granted yesterday at Westminster Magistrates' Court in respect of all six women whilst enquiries continue, a Metropolitan Police statement said.
A 21-year-old woman was arrested in hospital after being shot when officers fired laughing gas through the windows of a flat in north-west London and stormed the property.
Meanwhile, three men arrested during raids by heavily armed counter-terrorism officers as part of the same operation have been released without charge.
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"Officers have now completed the searches of all the addresses connected with the arrests," the Met said.
The news came as officers from the Met's Counter Terrorism Command (SO15) arrested a 30-year-old man at London's Heathrow Airport as he disembarked a flight from Istanbul, Turkey, yesterday.
The Met Police has conducted a series of raids and arrests in the last few weeks, including the arrest of a 27- year-old man carrying knives near the Houses of Parliament in London last week.
Britain's security services have reportedly identified 350 people who have returned to Britain from Syria and pose a potential terrorist threat.
More than 19,000 people were subjected to anti-terrorism security checks at ports and airports during 2016, according to latest figures.
This anti-terror activity has been further intensified since the March 22 attack on Parliament in London by Khalid Masood, which claimed four innocent lives.