At least twenty people have been killed and over one hundred injured as three blasts rocked downtown Mumbai. And the death toll is likely to rise even higher.

The Indian government has said the coordinated attacks were the work of terrorists, but no group has yet claimed responsibility. Indian Prime Minister, Manmohan Singh, condemned the blasts, and appealed to the people of Mumbai to remain calm and act with a united strength.

The first explosion took place in south Mumbai's Zaveri Bazaar, tearing through the district's famous jewelry market.

One minute later, a second blast hit the busy business district of Opera House.

And, several minutes after the first two blasts, a third explosion rocked the crowded neighborhood of Dadar in central Mumbai.

All three places are busy commercial and residential areas. They were bustling with people and traffic during the evening peak hours when the explosions took place.

The Indian Home Ministry has confirmed the explosions were terrorist attacks, saying Mumbai is now on high alert.

Indian Home Minister Palaniappan Chidambaram siad, "Apart from the three blasts, there is no information of any other blast or threat. The entire city of Mumbai has been put on high alert. I would appeal to the people of Mumbai and people all over the country to remain calm and maintain peace."

Police said an improvised explosive device was used to carry out at least one of the three attacks in Mumbai.

In the wake of the explosions, injured victims were rushed to nearby hospitals for medical treatment.

Its the first major terror attack to hit the city since the 2008 Mumbai attacks which killed 160 people.