Sen. Rand Paul of Kentucky said Tuesday that a clear-cut mission in Afghanistan after 9/11 has been “long gone” for years, openly questioning the United States’ current presence in the country.

“I think we had a clear-cut mission after 9/11, but that’s been long gone for many years now, and I think really that the Afghans need to step up and defend themselves, but there’s no reason for the U.S. to be involved there at all at this point,” Mr. Paul said on CNN. “And tragic accidents will happen when you’re involved with war, but I don’t see why we’re still involved in Afghanistan.”

Mr. Paul, a 2016 GOP presidential candidate, had been asked about an American airstrike that recently hit a charity hospital in Afghanistan, killing at least 22 people.

“There’s been a lot of confusion in the response: Was it an accident or was it done on purpose?” he said. “It appears as if the coordinates were given to somebody [because] they kept repeatedly bombing the same site.”

U.S. Army Gen. John F. Campbell testified Tuesday that the hospital had been “mistakenly struck” in the airstrike, but the group Doctors Without Borders has called the strike deliberate and has labeled it a war crime.

“But I think it goes to a bigger question, and this is a question that President Obama should have to answer: Why are we still at war in Afghanistan? What is the U.S. objective? What’s the U.S. mission, and why are we bombing anybody in Afghanistan?” Mr. Paul said.