Three men have been arrested on suspicion of Syria-related terrorism offences.
Police held a 26-year-old in Kent on Thursday, a 21-year-old in Sheffield on Friday and a 19-year-old in Coventry on Sunday.
A fourth man, aged 32, was arrested in Margate on Friday and released on bail pending further enquiries.
The three men are being questioned in the West Midlands, the force's counter terrorism unit said., external
More on this story and Coventry news
Detectives have been granted an extension of seven days to hold the two men in their 20s.
Officers have an initial 48 hours to hold the 19-year-old man for questioning.
The arrests were pre-planned and intelligence-led and there was no immediate threat to public safety, West Midlands Police said.
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