President Obama spoke about the newly announced nuclear agreement with Iran in a press conference today.

Obama said that the deal makes the U.S. and the world safer.

He acknowledged that it will require many years of hard work, vigilance and execution, but said the deal is our best means of assuring Iran does not get a nuclear weapon.

"The bottom line is this: This nuclear deal meets the national security interests of the United States and our allies. It prevents the most serious threat, Iran obtaining a nuclear weapon, which would only make the other problems that Iran may cause even worse," Obama said.

The president also took questions from the press. Read some highlights below.

What steps will you take to enable a more moderate Iran? And does this deal allow you to more forcefully counter Iran's destabilizing actions in the region?

"The point I've repeatedly made and, I believe, is hard to dispute is that it will be a lot easier for us to check Iran's nefarious activities, to push back against the other areas where they operate contrary to our interests or our allies' interests if they don't have the bomb."

"Unlike the Cuba situation, we're not normalizing diplomatic relations here. So the contacts will continue to be limited. But will we encourage them to take a more constructive path? Of course. But we're not betting on it."

Does it give you pause to see the deal praised by anti-American leaders in Iran and Syrian dictator Bashar al-Assad while it is being criticized by Israel and many members of the U.S. Congress?

"It does not give me pause that Mr. Assad or others in Tehran may be trying to spin the deal in a way that they think is favorable to what their constituencies want to hear. That's what politicians do."

"Based on the facts, the majority of Congress should approve of this deal. But we live in Washington, and politics do intrude. As I said in an interview yesterday, I am not betting on the Republican Party rallying behind this agreement."

Why did you lift the arms and ballistic missile embargoes? Are you concerned that arms to Iran will go to Hezbollah or Hamas, and what can you or a future president do to stop that?

"What I said to our negotiators was given that Iran has breached trust and the uncertainty of our allies in the region about Iran's activities, let's press for a longer extension of the arms embargo and ballistic missile prohibitions, and we got that."

"My key goal when I turn the keys over to the next president is that we are on track to defeat ISIL, that they are much more contained and we are moving in the right direction there."

Do you believe that the U.S. will need to work directly with Iran to negotiate a political settlement in Syria? And will the fight with ISIS require explicit cooperation with Iran?

"I do agree that we're not going to solve the problems in Syria unless there's buy-in from the Russians, the Iranians, the Turks, our Gulf partners. It's too chaotic, there are too many factions, there's too much money and arms flooding into zone. It's gotten caught up in both sectarian conflict and geopolitical jockeying. And in order for us to resolve it, there's going to have to be agreement among major powers that are interested in Syria that this is not going to be won on the battlefield. So, Iran is one of those players and it's important for them to be part of that conversation."

Can you tell the country why you are content to leave four Americans held captive in Iran out of the nuclear agreement?

"The notion I'm content as I celebrate with American citizens languishing in Iranian jails? That's nonsense. And you should know better. I've met with families of some of those folks. Nobody is content, and our diplomats and our teams are working diligently to try to get them out."

This agreement gives Iran a multi-billion dollar cash windfall. Why are you so confident they will spend that money at home and not on Hezbollah or other proxies?

"Do we think with the sanctions coming down Iran will have some additional resources for its military and for some of the activities in the region that are a threat to us, and threat to allies? I think that is a likelihood that they've got additional resources. Do I think it's a game-changer for them? No."

Are you holding out hope that Iran will suddenly change its behavior?

"No, I'm always hopeful that behavior may change for the sake of the Iranian people, as well as people in the region."

"But I'm not banking on that to say this deal is the right thing to do. Again, it is incumbent on the critics of this deal to explain how an American president is in a worse position 12, 13, 14, 15 years from now if in fact Iran decides to pull out of the MPT, kick out inspectors and go for a nuclear bomb. If that happens, that president will be in a better position than what would have if Iran, as a result of Congress rejecting this deal, decides, 'We're done negotiating, we're going after a bomb right now.'

"The choices would be tougher today than they would be for that president 15 years from now. And I have not yet heard logic that refutes that."