Staff and guests at the Pentahotel were advised to stay inside as precautionary measure

Veshh Kumar, a concierge at the hotel, said: "We had seen police activity since about 12.00pm then all of a sudden at about 4pm the bomb squad and the army arrived.

"The police told us to keep all the guests safe indoors. We don't know which building it was or what has taken place."

One resident, who lives in nearby Bishopgate Street, added: "Bath Row is cordoned off at the moment.

"There are about seven police vans and i would estimate over 35 police officers.

"The bomb disposal unit is there and I have seen a white bomb disposal robot. There is also an ambulance and two fire engines.

"I have never seen a police operation like this in my life.

"An officer told me it was a counter-terrorism operation and it is scary to think something like this is happening on the street next to mine.

"However it is reassuring to see police responding in this way with such a huge response."

A spokesperson for West Midlands Police said: "The arrests were intelligence-led and part of an on-going investigation."

West Midlands Fire Service also tweeted: "Fire crews have been supporting police colleagues with an ongoing operation in the Lea Bank area of #Birmingham."