WASHINGTON (Reuters) - The United States is on track to announce plans to supply India with 22 Guardian drones in a deal worth more than $2 billion, a source familiar with the deal said on Thursday.

The approval of the sale of the naval variant of the Predator drone comes ahead of a visit by Prime Minister Narendra Modi to the United States as he tries to revitalize relations with Washington. The deal would still require approval by Congress.

Securing agreement on the purchase of 22 unarmed drones is seen in New Delhi as a key test of defense ties that flourished under former President Barack Obama but have drifted under President Donald Trump, who has courted Asian rival China as he seeks Beijing’s help to contain North Korea’s nuclear program.

Modi’s two-day visit to Washington begins on Sunday.