The chairman of the U.S. House of Representatives Foreign Affairs Committee is reluctant to throw his support behind the historic nuclear deal with Iran.

Republican Ed Royce (of California) said Sunday he has "serious concerns" that the agreement does not meet the "standards necessary to protect the United States" and its allies.

Royce said Iran's sanctions relief is "more lifeline than modest."

He said the deal allows Tehran to keep the key elements of nuclear weapons-making capability.

Six world powers meeting with Iran in Geneva have reached a deal with Tehran to halt the progress of Iran's nuclear program.

U.S. Secretary of State John Kerry says the aim of the pact is to reach a comprehensive agreement with Iran, while the sanctions remain in place.

Representative Royce wants Kerry to come before the Foreign Affairs Committee "to address the many concerns with this agreement."

Royce is the author of the bipartisan Nuclear Iran Prevention Act that passed in the House in July and is currently pending in the Senate. The legislation would increase pressure on Iran, broaden economic sanctions, strengthen human rights sanctions and increase oversight of the implementation and enforcement of existing sanctions.