BEIJING, May 20 (Reuters) - Oil prices rose in early Asian trading on Monday, adding to last week's gains as rescuers searched for Iran's president after a helicopter crash in the oil-producing nation and after the U.S. bought crude to help refill the national stockpile.

Brent rose 26 cents, or 0.3% to $84.24 a barrel by 0049 GMT. U.S. West Texas Intermediate crude (WTI) gained 15 cents, or 0.2% to $80.21 a barrel.

Brent had ended the previous week up about 1%, its first weekly gain in three weeks, while WTI rose 2% on improved economic indicators from the U.S. and China, the world's largest oil consumers.

A helicopter carrying Iranian President Ebrahim Raisi crashed on Sunday, an Iranian official told Reuters. The lives of President Raisi and foreign minister Hossein Amirabdollahian were at risk, the official said.

Despite the volatility in the region, oil prices moved only slightly.

"The oil market remains largely rangebound and without any fresh catalyst we will likely have to wait for clarity around OPEC+ output policy in order to break out of this range," said Warren Patterson, head of commodities strategy at ING.

The Organization of the Petroleum Exporting Countries and allies, together called OPEC+, are scheduled to meet on June 1.

"The market also appears increasingly numb to developments on the geopolitical front, likely due to the large amount of spare capacity OPEC is sitting on," Patterson said.

The U.S. government took advantage of the recent drop in oil prices, saying late last week it had bought 3.3 million barrels of oil at $79.38 a barrel to help refill its Strategic Petroleum Reserve after a massive sale from the stockpile in 2022.

Supporting the market last week, signs of easing inflation in the U.S. boosted expectations of interest rate cuts, which could decrease the value of the dollar and make oil cheaper for holders of other currencies.

(Reporting by Colleen Howe; Editing by Sonali Paul)