NEW DELHI (REUTERS) - Human rights watchdog Amnesty said that a 10-hour raid at its southern Indian office by the financial crime investigating agency on Thursday (Oct 25) was part of the government's attempts at "silencing" its critics.

The Enforcement Directorate searched Amnesty's Bengaluru office on suspicion that it had violated foreign direct investment guidelines and said that further investigations were ongoing.

Prime Minister Narendra Modi's nationalist government has tightened surveillance on non-profit groups over the past four years, saying they are acting against India's interests.

Licences of thousands of foreign-funded groups, including one backed by the Bill & Melinda Gates Foundation, have been cancelled or suspended on charges such as misreporting of donations.

Amnesty, which regularly accuses India of human rights violations in the restive Himalayan region of Kashmir, said more than five officials from the Enforcement Directorate raided its office, ordered employees to stay put and searched their desks.

Employees were told to shut their laptops and not allowed to use their phones to call friends and families, Amnesty said, adding that it fully cooperated.

"ED raid on Amnesty India shows a disturbing pattern of the government silencing organisations that question power," it said on Twitter on Friday. "It is clear that the government wants to instil fear among Civil Society Organisations."

A government spokesman did not immediately reply to a text message seeking comment.

Critics says that the government has been using the foreign funding law as a tool to silence non-profit groups which have raised concerns about the social costs of India's rapid economic development.

In 2015, the Ministry of Home Affairs put the New York-based Ford Foundation on a watch list and suspended environmental campaigner Greenpeace's licence under India's Foreign Contribution Regulation Act (FCRA).

Last year, the government banned foreign funding for the Public Health Foundation of India, backed by the Bill & Melinda Gates Foundation, saying it used foreign donations to "lobby" for tobacco-control policy issues, "which is prohibited under FCRA".

In neighbouring Pakistan, the government has ordered at least 18 international aid agencies, most of them working on human rights issues, to leave the country, drawing criticism from countries such as the United States.