Sen. Chuck Schumer (D-NY) said Sunday he is “disappointed” with the nuclear deal reached Saturday between the U.S. and Iran.

“I am disappointed by the terms of the agreement between Iran and the P5+1 nations because it does not seem proportional,” he said in a written statement.

The agreement with Iran does not reduce the country’s nuclear capabilities enough, he added, making it more likely that the Senate will push for increased sanctions in December.

“Iran simply freezes its nuclear capabilities while we reduce the sanctions,” he said. “This disproportionality of this agreement makes it more likely that Democrats and Republicans will join together and pass additional sanctions when we return in December. I intend to discuss that possibility with my colleagues.”

Schumer said that reducing sanctions in Iran will not provide enough incentive for Iran to halt its nuclear program.

“It was strong sanctions, not the goodness of the hearts of the Iranian leaders, that brought Iran to the table, and any reduction relieves the psychological pressure of future sanctions and gives them hope that they will be able to gain nuclear weapon capability while further sanctions are reduced,” he said. “A fairer agreement would have coupled a reduction in sanctions with a proportionate reduction in Iranian nuclear capability.”