“For the second time in nearly two weeks, the United States carried out airstrikes against a facility used by Iran’s Islamic Revolutionary Guards Corps and its proxies in eastern Syria early Thursday, ratcheting up retaliation for a steady stream of rocket and drone attacks against American forces in Iraq and Syria. The strikes by two Air Force F-15E jets against a weapons warehouse in Deir al Zour Province, Syria, came after U.S. airstrikes on Oct. 27 against similar targets in eastern Syria failed to deter Iran or its proxies in Syria and Iraq, which the Biden administration has blamed for the attacks. Not only have the attacks continued — there have been at least 22 more since the American retaliatory strikes last month — but Pentagon officials said they have become more dangerous. Iran-backed militias have packed even larger loads of explosives — more than 80 pounds — onto drones launched at American bases, U.S. officials said. “This precision self-defense strike is a response to a series of attacks against U.S. personnel in Iraq and Syria by I.R.G.C.-Quds Force affiliates,” Defense Secretary Lloyd J. Austin III said in a statement. “The president has no higher priority than the safety of U.S. personnel, and he directed today’s action to make clear that the United States will defend itself, its personnel, and its interests.””