Global oil prices surged by as much as 4 percent Friday morning as markets absorbed news of the Donald Trump-ordered liquidation of Iran’s top military commander, Qassem Soleimani, who was killed in a U.S. strike on his convoy at Baghdad International Airport on Thursday. Amid concerns that tensions may disrupt oil supplies, Brent crude futures were up by nearly $3 at $69.16 per barrel, the highest since the September attack on Saudi Arabia’s Aramco refinery. U.S. West Texas Intermediate (WTI) crude futures touched $63.84 a barrel, the highest since May 1. “Certainly Iran is going to retaliate in some way—retaliations will come, as they have in the past, in what we call an asymmetrical way. They’re not going to confront the U.S. directly, but they will perhaps attack Saudi tankers again, maybe Saudi oil refineries again,” said John Tirman, executive director at the Massachusetts Institute of Technology Center for International Studies.