They are all being questioned at a police station in London.
On Tuesday in Israel a 21-year-old man from London, Asif Muhammad Hanif, is thought to have blown himself up in an attack that killed three people and injured 50.
The hunt is on for a second British man, 27-year-old Omar Khan Sharif from Derby, who is reported to have run away when his bomb failed to go off.
Police in Israel are searching hard for Sharif, and it's been rumoured that he's hiding in a safe house or has escaped to Palestinian territory.
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