"We firmly condemn these bombings as inexcusable acts targeted at innocent people," a foreign ministry statement said.

"We are resolved to continue our cooperation with the government of India to fight against terrorism," it said.

Forty-nine people were killed in a string of weekend bomb attacks in the western city of Ahmedabad. A wave of bombings earlier struck the southern high-tech hub of Bangalore, leaving one dead.

Japan has in recent years sought warmer relations with India, in part to counterbalance Tokyo's often uneasy ties with China.