President Barack Obama strongly defended the nuclear negotiations with Iran at the end of the US-GCC (Gulf Cooperation Council) summit in Riyadh, Saudi Arabia, on Thursday.

Speaking at the conclusion of the summit, Obama said the outcome of the negotiations proved it was the right approach to take despite the Saudis and Gulf countries’ concerns that the United States was “naïve” when dealing with Iran.

“John F. Kennedy and Ronald Reagan still negotiated with the Soviet Union even when the Soviet Union was threatening the destruction of the U.S.,” he said. “That’s the same approach we have to take. Even as Iran is calling us the great Satan, we were able to get a deal done that reduces their nuclear stockpiles. That’s not a sign of weakness, that’s a sign of strength.”

The President maintained that the Iran nuclear deal “cut off every single one of Iran’s pathways to a nuclear weapon.” But he said the United States continues to have “serious concerns” about Iran’s behavior in the region. He also raised the possibility of diplomacy to resolve conflicts in Yemen and Syria, since “none of our nations have an interest in conflict with Iran.”

“We’ll remain vigilant to ensure that Iran fulfills its commitments, just as we will fulfill ours,” Obama promised.

Thursday’s summit was preceded by bilateral talks that Obama held with Saudi King Salman on Wednesday in which the two leaders sought to restore the relationship strained in the aftermath of the Iran deal. According to U.S. officials, Obama pressed the Saudi King to be more open to engaging in diplomacy and to find alternatives to direct confrontation with Iran’s leadership.

“We made very clear to the leaders last night and today on the subject of Iran that our partners, our friends in this region are in the room with us here, and Iran, on the other hand, has in many ways been confrontational not just to the countries here in the GCC, but to the United States as well, and that we share their concerns about Iran’s ballistic missile program, its destabilizing activities in the region, its ongoing support for terrorism,” Deputy National Security Adviser Ben Rhodes told reporters on Thursday. “And, in fact, many of the capabilities that we’re developing on the defense side through this process are focused on countering Iranian actions.”

Rhodes said President Obama made the point to Gulf leaders that their concern with Iran “should not foreclose the potential for diplomatic engagement if there’s an ability to resolve problems. And a recent example, of course, is the nuclear deal where, despite all of our concerns about Iran’s behavior, we were able to see a significant rollback in the Iranian nuclear program because we pursued a diplomatic process.”