Sen. Jeff Flake (R-AZ), one of a few Republican senators who did not sign a letter warning Iranian leaders against a nuclear deal with the United States, said on Tuesday that he doesn’t think the letter is “productive.”

“I just didn’t think it was productive during this time when there are very tough negotiations going on. They’re tough enough without introducing this element,” he told CNN’s Wolf Blitzer.

But when Blitzer asked if the 47 senators who did sign the letter were trying to hurt President Obama or help Iran, Flake said he didn’t think so.

“I agree with Susan Collins saying that I don’t think the Iranians are that concerned about what 47 senators think,” Flake said. “But I was more concerned about our allies. Iran is at the table because these sanctions have bitten pretty hard, these multilateral sanctions. We’ve got to keep this coalition together.”

Flake added that he believes Congress should weigh in on the nuclear deal with Iran, but that he would like to see the deal reached before coming to a conclusion on the negotiations.

“I know there are a lot of people who don’t think this agreement is going to be a good one. I think we all have our doubts whether this is going to be an agreement worth pursuing,” he said. “But my own view — I can only speak for myself — is that we ought to take every opportunity to have a negotiated agreement rather than the alternative. The alternative isn’t good.”

Sen. Bob Corker (R-TN), chair of the Senate Foreign Relations Committee, also declined to sign the letter, and said he didn’t think the letter was “constructive.”