By Dhwani Pandya, Shilpa Jamkhandikar and Shivam Patel MUMBAI/NEW DELHI (Reuters) -The finance chief of India's Adani Group on Friday rejected U.S. allegations that executives, including Chairman Gautam Adani,

NEW DELHI -- Asia’s controversial richest man, Indian tycoon Gautam Adani, is again in the spotlight. His companies’ stocks plunged up to 20% on Thursday after he was indicted by U.S. prosecutors on charges he duped investors in a massive solar energy project in India by concealing that it was being facilitated by an alleged bribery scheme.

Congress and other opposition parties accuse the government of Prime Minister Narendra Modi of protecting billionaire Gautam Adani.

Some nations and investors have either scrapped deals or halted investments in the Adani Group, after the United States indicted its billionaire chairman Gautam Adani for alleged bribery and fraud to win contracts for a group company,