1 of 3 | U.S. Vice President JD Vance holds a press briefing Tuesday in the James S. Brady press briefing room at the White House in Washington, D.C. Photo by Samuel Corum/UPI | License Photo

May 19 (UPI) -- Vice President JD Vance took questions from reporters Tuesday at a White House press briefing

, reiterating President Donald Trump's repeated assertion that the conflict in Iran is meant to keep the country from developing a nuclear weapon but that it is "not a forever war."

"We want to keep the number of countries that have nuclear weapons small, and that's why Iran cannot have a nuclear weapon," he said during the briefing, "on top of all the other things that we might be worried about, that they themselves could use it, that they could use it in leverage and economic control or economic negotiations."

Vance was the second person, following U.S. Secretary of State Marco Rubio, to stand in for White House press secretary Karoline Leavitt, who is on maternity leave.