Cities across India are on high alert following a series of explosions in Mumbai.

As many as 18 people are feared dead following three co-ordinated explosions in the commercial hub of the city late yesterday, with dozens feared injured.

No group has so far claimed responsibility for the attack, which is the worst in the city since November 2008, when gunmen killed 165 people in a three-day raid.

Pakistani-based militants were blamed for the 2008 attacks, with the government in Islamabad was quick to condemn the latest attacks.

India’s home minister P Chidambaram said he believed the latest Mumbai blasts were “a co-ordinated attack by terrorists”.

British travellers have been warned to be on high-alert when travelling in the country.

“There is a high threat from terrorism throughout India. Recent attacks have targeted public places including those visited by foreigners,” read a statement from the British Foreign & Commonwealth Office (FCO).

“Following explosions major cities in India remain on high alert and British nationals should exercise caution.”

British foreign secretary William Hague was quick to condemn the attacks, calling them a “deplorable acts of terrorism”.

He added: “We are committed to working with the Indian government and our allies and partners to combat the threat from terrorism.”

The three explosions happened with a fifteen minute window at around 18:00 yesterday.

They hit the Zaveri Bazaar, the Opera House and Dadar, a residential district.