The Federal Reserve may expand its purchases of U.S. Treasuries, or quantitative easing, beyond its $600 billion target, said Vincent Reinhart, who was the Fed’s chief monetary-policy strategist from 2001 until September 2007.

“They do all of QE2 because they don’t want to be seen as succumbing to outside pressure,” Reinhart, now a scholar at the American Enterprise Institute in Washington, said in an interview on Bloomberg Television’s “Street Smart” with Carol Massar. “I think there is a chance there will be QE3 and it is going to be because the unemployment rate is above 9 percent,” he said, referring to a third round of purchases.

The Fed on Dec. 14 reaffirmed its plan to buy $600 billion in Treasuries through June, expanding record stimulus to try to reduce 9.8 percent unemployment and keep inflation from dropping. Chairman Ben S. Bernanke is trying to boost growth after near-zero interest rates and $1.7 trillion in securities purchases helped pull the economy out of recession without bringing down joblessness close to a 26-year high.

Columbia University Professor Charles Calomiris, speaking on the same broadcast, disagreed with Reinhart that more easing might be added.

“I don’t think so,” he said. “My view is it is probably not on the table.”

Calomiris said the Fed would be “very slow” to raise its target federal funds rate from near zero.

“They keep the short rate where it is for the rest of” 2011, Reinhart said. “They are going to have to be forced to tighten by events.”

Calomiris was among a group including former Republican government officials and economists who sent Bernanke a letter in November that urged an end to his expansion of monetary stimulus, saying it risks an inflation surge.