Gold prices on Tuesday sank to their lowest levels in nearly a month, as the U.S. dollar firmed and oil prices climbed with investors eyeing a crush of central bank interest rate decisions this week.

Spot gold dropped 1.8% to settle at $4,597.06/oz and gold futures declined 1.8% to settle at $4,609.35/oz.

A tracker of the U.S. dollar against a basket of major currencies strengthened, making bullion more expensive for overseas buyers. The greenback has been floating just above pre-war levels, as traders view it as a relative safe-haven amid an oil supply shock due to the U.S.’s status as a major energy exporter.

The average U.S. gasoline price rose to its highest level in nearly four years, jumping more than 40% since the U.S. and Israel attacked Iran at the end of February, according to data from the American Automobile Association or AAA.

Prices at the pump were near $4.18 a gallon on Tuesday, up 11 cents a gallon in this month and $1.19 a gallon since late February, AAA data showed.

Bitcoin fell below $77,000 on Tuesday after another failed breakout attempt, as a continued impasse between the U.S. and Iran and caution ahead of key central bank meetings dented risk appetite.

The world’s largest cryptocurrency was last down 0.5% at $76,377.5 by 17:38 ET (21:38 GMT).

The dollar firmed on Tuesday, as investors assessed an apparent deadlock in talks between the U.S. and Iran as well as a raft of central bank interest rate decisions this week.

At 16:52 ET (20:52 GMT), the U.S. dollar index, which tracks the greenback against a basket of six major peers, rose 0.2% to 98.64.