The Indian government has slammed a US move to impose a new tax that seeks to help victims of the September 11 attacks but will raise the costs for technology companies in the United States.

The US Congress and the Senate on Wednesday passed a legislation that seeks to make the Indian firms such as Infosys, TCS and Wipro pay for the victims of September 11 terror attacks. India has protested the bill, calling it a 'retrograde step' in Indo-US trade relations.

The legislation, to be effective from July next year, will raise a $4.2 billion to help the victims of September 11 terrorist attacks by levying a new 2% excise tax on goods and services purchased from foreign suppliers based in countries such as India and China.