President Barack Obama in his final speech on national security said diplomatic engagement is “required” to resolve Middle Eastern conflicts, including between Israel and the Palestinians.

The remarks came as top officials in the outgoing administration hope to influence President-elect Donald Trump to maintain its diplomatic initiatives, particularly regarding the Israeli-Palestinian conflict and the Iran nuclear deal.

“Just think about what we’ve done these last eight years without firing a shot,” Obama said Tuesday, addressing troops at an Air Force base in Tampa. “We’ve rolled back Iran’s nuclear program. That’s not just my assessment, that’s the assessment of Israeli intelligence, even though they were opposed to the deal.”

Obama said diplomacy helps keep Americans safe. “Sustained diplomatic efforts, no matter how frustrating or difficult they sometimes appear, are going to be required to resolve the conflicts roiling in the Middle East, from Yemen, to Syria, to Israel and Palestine,” he said. “And if we don’t have strong efforts there, the more you will be called upon to clean up after the failure of diplomacy.”

President-elect Donald Trump delivered mixed messages on the Israeli-Palestinian conflict. He has said he is eager to find a solution, but aides have also said they will defer to Israel on the matter, and would not press Israel hard to make concessions.

Trump also has said the Iran deal is a bad one, and that he would reassess it, but has not said he would scrap it.