Three separate, but coordinated explosions killed at least 21 people in Mumbai, India Wednesday. Another 141 were injured.

The attack took place during rush hour in India's busy financial district. The blasts hit three crowded neighborhoods within minutes of each other.

Wednesday's explosions came nearly three years after Pakistan-based militants laid siege to the city of Mumbai, killing 166 people.

The latest bombing is the worst terror attack in India since the 2008 incident.

Prime Minister Manmohan Singh condemned Wednesday's blasts and urged his people "to remain calm and show a united face."

U.S. President Barack Obama also condemned the "outrageous attacks."

"The American people will stand with the Indian people in times of trial, and we will offer support to India's efforts to bring the perpetrators of these terrible crimes to justice," he said in a statement.

"I have no doubt that India will overcome these deplorable terrorist attacks," he said.

No one has claimed responsibility for the attacks.