The dollar strengthened on Wednesday, helped by an uptick in safe haven demand following fresh strikes between the U.S. and Iran and higher rates.

Meanwhile, the Japanese yen hit the key 160 level for a second straight day, sparking warnings from Japanese authorities about a possible intervention in currency markets.

At 14:58 ET (18:58 GMT), the U.S. dollar index, which tracks the greenback against a basket of six major peers, was up 0.3% to 99.52.

Gold prices ticked up slightly on Tuesday, but gains were limited by increasing uncertainty over the state and extent of peace talks between the U.S. and Iran amid mixed messaging from both parties.

Tehran for a second straight day said that exchange of messages with Washington were halted, but President Donald Trump and Secretary of State Marco Rubio asserted that negotiations were still ongoing. U.S. equities and the dollar were also rangebound amid the conflicting signals, while oil prices rose.

Oil prices climbed about 1% to a one-week high in volatile trade on Tuesday as the market waited for news on the Iran war, with Tehran reviewing a proposed agreement with the U.S. to halt the conflict.

Brent futures rose $1.02, or 1.1%, to settle at $96.00 a barrel, while U.S. West Texas Intermediate (WTI) crude rose $1.60, or 1.7%, to settle at $93.76.

Those were the highest closes for both benchmarks since May 26.

The U.S. dollar ticked higher on Monday, boosted by a renewed bout of safe haven demand after Iran said it would suspend mediated negotiations with the U.S. following fresh strikes and an Israeli military operation in Lebanon.

President Donald Trump attempted to calm tensions somewhat after saying a planned Israeli attack on Lebanon’s capital city Beirut would not take place and that talks with Iran were ongoing.

The dollar is coming off a nearly 1% rise for May, helped by its attractiveness as a safe haven asset and expectations for higher interest rates.