By Aftab Ahmed

GANDHINAGAR, India (Reuters) -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, U.S. Treasury Secretary Janet Yellen said on Monday.

After a bi-lateral meeting with India's finance minister Nirmala Sitharaman on the sidelines of a G20 meeting, 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.

She also said the two countries are close to reaching an agreement on the global minimum tax system.

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.

Sitharaman said she was looking forward to furthering bilateral interests through development cooperation and new investment opportunities through alternate investment platforms for renewable energy.

"As we look ahead, we reaffirm our commitment to achieve substantial outcomes through close engagement," she added.

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

(Writing by Swati Bhat and Shilpa Jamkhandikar; Editing by Christian Schmollinger and Lincoln Feast.)