The United States is working with India to develop an investment platform to lower the cost of capital and increase private investment to fast-track India's energy transition, US Treasury Secretary Janet Yellen said on Monday.

"We are close to reaching an agreement on the global minimum tax system," said Yellen, after a bilateral meeting with Finance Minister Nirmala Sitharaman on the sidelines of a G20 meeting.

ALSO READ | US sees India as an indispensable partner in friendshoring, says Treasury Secretary Yellen

The visit is Yellen's third to India this year, indicating the growing closeness between the two countries.

The improvement in bilateral relations was highlighted during Prime Minister Narendra Modi's state visit to Washington last month which saw a slew of defence and high technology deals being signed.

Yellen said the two nations have been collaborating across a range of economic issues, including commercial and technological collaboration and strengthening supply chains.

"In particular, we look forward to working with India on an investment platform to deliver a lower cost of capital and increased private investment to speed India's energy transition," she said.

Yellen will visit Vietnam after the G20 finance meetings end on July 18.