Two males have been arrested after packages containing liquid had been despatched to various hospitals throughout the UK, the Met Police has confirmed.
The drive mentioned a 29-year-old man from Brent and a 37-year-old man from Harrow, each in north-west London, had been arrested by counter-terror officers on Thursday on suspicion of Malicious Communications Act offences.
Not one of the packages has up to now been discovered to comprise something hazardous.
The lads had been bailed till late August.
Inquiries are persevering with, the Met added.