Russian President Vladimir Putin, who will visit India this week for an annual bilateral summit, will sign an agreement to supply New Delhi with S-400 air defence systems, his aide Yury Ushakov said on Tuesday.

“The president is leaving for India on October 4,” Ushakov, who is Putin’s top foreign policy aide, told AFP. “The value of the contract will be more than $5 billion [Rs 36,600 crore].”

The United States has expressed concerns about the proposed sale, the negotiations for which concluded in May. The Donald Trump administration has imposed sanctions on Russia and other countries that sign military deals with it.

However, on May 28, US Arms Service Committee Chairperson Mac Thornberry said Washington had made the sanctions flexible to provide “breathing room” for countries such as India. In August, the Pentagon said the United States would consider sanctions against India if it signs the deal.