(CBS) – U.S. Sens. Dick Durbin and John McCain made a joint, harmonious appearance in Chicago on Monday and faulted U.S. intelligence for monitoring the German chancellor’s personal cell phone.

Durbin, D-Illinois, and the Arizona Republican disagree politically on a number of issues but concurred that bugging Angela Merkel’s calls was wrong.

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“Collecting information around the world is critical to keeping America safe. We must continue to do so. But there must be limits to that collection. We’ve got to make certain that we do not abuse or destroy our relationship with key allies,” Durbin told reporters after an appearance at the City Club.

Said McCain: “Eavesdropping on someone’s private cellphone obviously is something that’s offensive to the chancellor of the federal Republic of Germany.”

President Obama, swearing in a new FBI director on Monday, did not mention the eavesdropping on allies. His spokesman declined to say when he found out about it — only that it had stopped.

For McCain, that wasn’t enough.

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“We need to know who knew and when they knew it. But also I think it calls for congressional oversight hearings and probably, perhaps a select committee, to look at the whole issue of surveillance,” he said.

In what’s an increasingly rare sign of bipartisanship, Sens. McCain and Durbin had high praise for each other.

Durbin–co-chair of Barack Obama’s 2008 presidential campaign–called McCain, the former GOP nominee, an extraordinary public servant.

He credited McCain as one a few Republicans that helped end the government shutdown.

Both McCain and Durbin agreed on the need for immigration reform and Hillary Clinton’s strength as a presidential candidate.

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McCain called Clinton’s work as Secretary of State “outstanding” and said she would be a considered a formidable candidate.