WASHINGTON – A letter signed by 367 House members to President Obama highlights what they describe as "grave and urgent issues" relating to negotiations to rein in Iran's nuclear ambitions.

The letter, dated March 20 and released Monday by the House Foreign Affairs Committee, cites concerns about the size of Iran's uranium enrichment program, its lack of cooperation with international inspectors and the need for an intrusive inspection regime.

In any agreement, "Congress must be convinced that its terms foreclose any pathway to a bomb, and only then will Congress be able to consider permanent sanctions relief," according to the letter signed by 84 percent of House members.

"A final comprehensive nuclear agreement must constrain Iran's nuclear infrastructure so that Iran has no pathway to a bomb, and that agreement must be long-lasting," the letter said.

Those signing the letter include such Republicans as Speaker John Boehner and Majority Leader Kevin McCarthy and such Democrats as Steny Hoyer, the minority whip, and Eliot Engel.

The lawmakers said they remain "hopeful that a diplomatic solution preventing Iran from obtaining a nuclear weapon may yet be reached," and told Obama, "we want to work with you to assure such a result."

Negotiators from the United States and five other nations are seeking to ensure that Iran's nuclear program is peaceful in exchange for relief from trade curbs that have squeezed the Islamic Republic's economy. Issues being discussed include the nuclear capacity Iran should be allowed to keep, the nature of inspections and the pace of relief from sanctions, especially on oil exports. As an end-of-March deadline for a framework agreement nears, leaders on each side sought to keep pressure on the other.

Obama has urged lawmakers to be patient as negotiators try to reach a deal with Iran and to hold off on taking other actions, including further sanctions, unless the talks fail.

The Obama administration has denounced a March 9 letter sent by 47 Republican U.S. senators to political leaders in Iran as an attempt to undermine the president on a foreign policy matter for political purposes.

Of the bipartisan letter sent to Obama from House members, Boehner spokesman Michael Steel declined to comment on Monday, saying the letter speaks for itself.

Senate Foreign Relations Committee Chairman Bob Corker of Tennessee has said his committee will vote on a bill to require congressional review of any final nuclear agreement. The panel is set to consider the measure on April 14. The House letter didn't say whether the chamber will pursue its own legislation.