WASHINGTON, Sept. 18 (Xinhua) -- U.S. President Barack Obama on Thursday nominated an Indian-American to be his new ambassador to India, just before Indian Prime Minister Narendra Modi comes for a maiden visit at the end of the month.

Obama named Richard Rahul Verma to fill in a post left vacant since March, a nomination that has to be approved by the Senate.

Verma served as assistant secretary of state for legislative affairs from 2009 to 2011 and a senior adviser to Senate Majority Leader Harry Reid from 2002 to 2007.

He is senior counselor at Steptoe & Johnson LLP and the Albright Stonebridge Group as well s a senior national security fellow at the Center for American Progress, according to the White House.

Obama will discuss with Modi "a range of issues of mutual interest in order to expand and deepen the U.S.-India strategic partnership" during his visit on Sept. 29-30, the White House said.

Washington denied Modi a visa in 2005 for his alleged role in the communal riots in the state of Gujarat in 2002, in which over 1,000 people, mostly minority Muslims, were killed.

Modi, then chief minister of the state, was criticized for failing to act to prevent the riots.

Bilateral relations were chilled after the U.S. arrest in December of India's then deputy consul general in New York Devyani Khobragade over visa fraud charges escalated into a major diplomatic row.