The dollar climbed in Asia on Monday on signs that talks between the United States and Iran were deadlocked, leaving the vital Strait of Hormuz all but shut and sending oil prices higher.

Investors headed into Monday on edge as Trump’s rejection of Iran’s ceasefire proposal fueled concerns about a prolonged Middle East conflict.

While the Strait of Hormuz remained largely closed, keeping global energy supplies tight, oil prices jumped $3 a barrel on Monday.