Thames Valley Police said the six suspects, aged between 23 and 57 from Portsmouth, Farnborough and Greenwich, were arrested by the South East Counter Terrorism Unit this morning.
They were arrested in connection with "conflicts overseas" and were "not linked to any immediate threat to local communities", a police spokesperson said.
Today's arrests involved two men, aged 26 and 23, from Portsmouth, a 23-year-old woman from Farnborough, and a 29-year-old woman from Greenwich, south-east London, who were all arrested on suspicion of commission, preparation and instigation of acts of terrorism.
A 48-year-old woman from Portsmouth was also arrested for failing to disclose information about acts of terrorism.
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