NEW DELHI, Nov 1 (Reuters) -

U.S. Treasury Secretary Steven Mnuchin will hold talks with Indian leaders in New Delhi on Friday, Indian official said, as part of a tour to build support against Iran over its nuclear program and its ties to militant networks.

On Wednesday, the United States and six Gulf countries agreed to jointly impose sanctions on 25 corporations, banks and individuals linked to Iran's support for militant networks including Hezbollah, the U.S. Treasury Department said.

Mnuchin, accompanied by Donald Trump's senior advisor and son-in-law Jared Kushner, began a regional tour from Oct. 25 through Saudi Arabia, Israel, United Arab Emirates, India and Qatar.

In New Delhi he will hold talks with Finance Minister Nirmala Sitharaman, an Indian government official said. No details were provided.

Other members of the U.S. delegation include under secretary for international affairs Brent McIntosh and assistant secretary for terrorist financing and financial crimes Marshall Billingslea.

India, a long-time buyer of Iranian oil, halted purchases in May in the wake of renewed U.S. sanctions, and its refiners are now buying more crude from some suppliers, including Mexico, and signed new contracts with U.S. firms.

Sanctions were reimposed on Tehran by President Donald Trump after he withdrew the United States from Iran's 2015 nuclear pact with world powers.

Aside from throttling Iran's oil exports, the sanctions also cut Iranian banks' ties to the financial world. Mnuchin and the U.S. delegation will travel to Mumbai, India's financial capital, on Saturday for talks with Reserve Bank of India Governor Shaktikanta Das and other central bank officials, before meeting later with Indian business leaders, a RBI official said.