Khatami made the comments, his first public remarks since the International Atomic Energy Agency issued the October 31 deadline, during a meeting with Belgium's outgoing ambassador, ISNA said.
Just when Iran had begun talks with the IAEA on signing an agreement that would allows snap inspections of Iranian nuclear sites, "the agency adopted a resolution under foreign pressure that is unjust toward Iran," he was quoted as saying.
The IAEA board imposed the deadline on September 12, also urging Iran to suspend enriching uranium, which the United States claims could be used to make nuclear bombs.
The resolution demands Tehran answer all the agency's questions regarding its enrichment activities, provide unrestricted access to UN inspectors and a detailed list of its nuclear-related imports.
"We ask of the IAEA that it recognize our right to have access to civilian nuclear energy and to provide its aid in conformity with international regulations, and we give the agency the assurance that the Islamic Republic of Iran does not seek to acquire the atomic bomb," Khatami said.
The UN agency has announced that its inspectors will return to Iran Sunday in the hope of leading Tehran to prove that it is not developing nuclear weapons, as the United States and some other countries charge.
The inspectors will investigate allegations that Iran is reprocessing and enriching uranium. They will concentrate on an enrichment facility at Natanz, 250 kilometers (155 miles) south of Teheran where traces of fuel with possible military application have been detected.
In Vienna on Thursday, diplomats reported that inspectors had found more traces of highly enriched uranium in Iran but are not certain whether it was produced in the country or imported on contaminated equipment.
The traces were said to be found in environmental samples carried out in the first half of August at the Kalaye Electric Co., a plant Iran says was used for storing equipment and was not part of their nuclear power program.