India called for the U.S. to stop any spying activities as it sought an explanation for a media report that the National Security Agency conducted surveillance on Prime Minister Narendra Modi’s ruling party.

U.S. diplomats today told Indian officials that they’d investigate claims Modi’s Bharatiya Janata Party was among six political groups around the globe that President Barack Obama’s administration spied on, according to Syed Akbaruddin, a spokesman for India’s Ministry of External Affairs. They were reported by the Washington Post, citing documents from former NSA contractor Edward Snowden.

“Should this have happened it is highly objectionable,” Akbaruddin told reporters today in New Delhi.

U.S.-India relations plunged to their lowest in 15 years at the end of last year after an Indian diplomat was arrested in New York, strip searched and charged with visa fraud for allegedly underpaying her babysitter. The row threatened to jeopardize a growing economic relationship as annual trade in goods and services between the countries nears $70 billion.

The BJP swept to power in a May election with the biggest mandate for an Indian party in 30 years. The U.S. had imposed sanctions on the government when the party was last in power for detonating nuclear weapons in 1998.

The U.S. denied Modi a visa in 2005 over his alleged role in 2002 riots that killed about 1,000 people, mostly Muslims in the state of Gujarat where he was chief minister. He was barred from the country under rules that ban officials who were responsible for “severe violations of religious freedom.”

A U.S. official met him in February for the first time since the visa denial, and Modi is planning to meet with Obama in September, according to India’s foreign ministry. Modi has denied any wrongdoing over the Gujarat riots. U.S. Senator John McCain, who met India’s Foreign Minister Sushma Swaraj in New Delhi today, canceled a scheduled press conference.

The U.S. also spied on Egypt’s Muslim Brotherhood and National Salvation Front, the Pakistan Peoples Party, Lebanon’s Shiite Amal Movement, an ally of Hezbollah, and the Bolivarian Continental Coordinator, according to the Post, citing a Snowden document dated 2010.