The war between Israel and Iran has raised concerns that Iran could try to close the Strait of Hormuz, the world’s most important oil chokepoint.

Oil prices oscillated on Monday, touching a five-month high before erasing most gains as oil and gas transit continued on tankers from the Middle East after U.S. airstrikes against Iran at the weekend.

Analysts with ING financial group outlined four possible avenues for Iran: full escalation that also draws in other nations such as China or Russia; disruption of the Strait of Hormuz; active or passive support for terrorist attacks in the U.S. and Europe; or taking no action at all.

Oil prices tumbled $5 a barrel, or over 6%, on Monday after Iran attacked a U.S. military base in Qatar in retaliation for U.S. attacks on its nuclear facilities at the weekend, and took no action to disrupt oil and gas tanker traffic through the Strait of Hormuz.

Oil and gas prices rose after the U.S. struck Iran’s nuclear infrastructure over the weekend, but the gains moderated early in the European trading session.