April 2 (Reuters) - Rivian reported a 36% decline in first-quarter deliveries on Wednesday, as the electric-vehicle maker grapples with weak demand, sending its shares down 6.7% in morning trading.

The company delivered 8,640 vehicles in the quarter ended March 31, down from 13,588 a year earlier. The deliveries, however, exceeded analysts' average estimate of 8,200, according to Visible Alpha.

The company's chief financial officer, Claire McDonough, had said in February vehicle deliveries would be lower this year due to soft demand, partially because of the impact of fires in Los Angeles.

Rivian and other EV makers have been battling tough demand for their vehicles as consumers opt for cheaper hybrid and gas-powered models in an uncertain economic and political environment.

U.S. president Donald Trump's tariff policies could accelerate inflation and increase prices of automobiles, further making consumers wary of committing to big purchases.

Rivian CEO RJ Scaringe told Reuters earlier this year that the company expects higher costs from tariffs on Mexico and Canada as it has a supply chain footprint in both the countries.

The company produced 14,611 vehicles in the first quarter, compared with 13,980 vehicles a year ago.

It reaffirmed its annual deliveries forecast and expects to announce its quarterly financial results on May 6, after markets close.

Rivian is banking heavily on the roll-out of its less expensive R2 next year to reinvigorate demand and compete with EV heavyweight Tesla's Model Y.