WASHINGTON - Iran has responded with silence to a UN-backed deadline for its government to answer questions on years of suspected research into atomic explosions.Tehran failed to publicly address the Monday deadline, imposed by the United Nations Atomic Energy Agency and watched closely by members of the UN Security Council.Member states on the council, along with Germany, are attempting to forge a comprehensive deal with Iran that will end international concerns over the nature of its nuclear program.The IAEA also declined to comment on whether the Iranians had complied with their demands. The agency releases public reports on its progress with Iran on a quarterly basis. For several years, the IAEA has asked Iran to provide answers to a long list of questions concerning its atomic weapons research. The agency, and the Security Council, both agree that evidence strongly suggests the country's nuclear program harbors possible military dimensions.Much of that evidence, collected by individual state-run intelligence agencies, has remained secret. But IAEA reports consistently indicate that their suspicions have been substantiated with intelligence beyond what is in their own capacity to collect.Iran claims its nuclear work amounts to a peaceful energy program, and that its ability to enrich uranium is guaranteed under the Nuclear Nonproliferation Treaty. The United States and its allies, however, say that Iran has been in violation of its international obligations for over a decade.The agency specifically wants Iran to address concerns into its research over explosives experimentation, as well as studies into nuclear explosive yields.Questions over weaponization research hit at the core of the nuclear impasse between Iran and the international community: whether Iran's leaders have lied to the world, and have sought or entertained the illicit pursuit of atomic bombs despite their claims to the contrary— and on several occasions, their insistence that Islam bans the Islamic Republic from acquiring such arms.Iran has promised to cooperate with the IAEA since Hassan Rouhani, widely seen as a pragmatist, was elected Iranian president in mid-2013.Tehran agreed in May to take five steps by late August, including information on alleged explosives experimentation, and studies related to calculating nuclear explosive yields.Comprehensive nuclear negotiations between the US, United Kingdom, France, China, Russia, Germany and Iran were extended after six months of talks concluded in July with no agreement. The parties have granted themselves another four months, until November 24, to reach a deal.Reuters contributed to this report.