(CNN) -- Iranian officials, outraged over attacks against two nuclear scientists, say they suspect Israel and Western countries were responsible for incidents that Iran continues to investigate.
"The main suspects are those Western countries that claim to advocate human rights but use it as a political tool to exert pressure on other countries," said Ramin Mehmanparast, the Iranian Foreign Ministry spokesman, according to Iran's state-run Press TV. "All those countries that are threatening the Islamic Republic of Iran ... are the main suspects behind such incidents."
Assailants on motorcycles attached bombs to cars carrying Majid Shahriyari and Fereydoun Abbasi on Monday. Shahriyari died but Abbasi and his wife escaped with minor injuries. Shahriyari's wife and driver were injured.
The two were nuclear physics professors at Shahid Beheshti University in Tehran, according to Iran's official Islamic Republic News Agency.
The Institute for Science and International Security, a non-profit group in the United States focused on stopping the spread of nuclear weapons, also identified the two as nuclear scientists.
Both were members of the Basij, Iran's volunteer paramilitary group, semi-official Fars news agency said.
Iranian lawmakers condemned the attack Tuesday and urged police to identify the attackers. On Monday, President Mahmoud Ahmadinejad blamed Israel and Western powers.
Mehmanparast didn't rule out a link between the attacks and remarks from the head of the British intelligence agency MI6 "about challenging Iran's civilian nuclear program," Press TV reported.
Thousands of students rallied at the school Tuesday and chanted slogans against the United States, Israel and Britain. They demanded the attackers be brought to justice.
Asked about the attacks, U.S. State Department spokesman P.J. Crowley said Monday that "all I can say is we decry acts of terrorism wherever they occur, and beyond that, we do not have any information on what happened."
A United Nations resolution cited Abbasi as a "nuclear scientist," the state-run Press TV said. That suggests that the "perpetrators behind the assassination could be traced through those who included the professor's name in the U.N. resolution," Press TV said.
The resolution, from March 2007, identifies Abbasi as one of several people "involved in nuclear or ballistic missile activities" in Iran. It does not call him a "nuclear scientist" but describes him as a scientist for the Senior Ministry of Defense and Armed Forces Logistics who has links to the Institute of Applied Physics.
Foad Izadi, a lecturer at the University, told Press TV on Monday that the resolution was a "hit list."
"Those atomic physics professors were very active in Iran's peaceful nuclear energy [program] ... during the past seven to eight years. ... The United States and the Zionist regime [Israel] have been trying different methods to stop Iran's peaceful nuclear program," Izadi said.
The European Union froze Abbasi's assets last month as it imposed additional sanctions on Iran.
The U.N. resolution says Abbasi worked closely with another scientist, Mohsen Fakhrizadeh-Mahabadi, who led the Physics Research Center in Iran. The International Atomic Energy Agency had sought to interview Fakhrizadeh-Mahabadi, but Iran declined to allow that, the resolution says.
A separate bomb attack in Tehran in January killed "an Iranian university professor and nuclear scientist" identified as Massoud Ali Mohammadi, Fars news agency said.
The attacks come amid international worry over Iran's nuclear aspirations.
U.S. diplomatic documents leaked by WikiLeaks indicate that along with Western nations and Israel, Arab countries, including Saudi Arabia, also are concerned about Iran's nuclear program.
There have been efforts by international powers to head off what many believe is Iran's work to develop nuclear weaponry.
Ahmadinejad said Tuesday that Iran has agreed to another round of nuclear talks with the United States and other nations.
A spokeswoman for Catherine Ashton, the European Union's foreign policy chief, said the talks will take place in Geneva, Switzerland, on Monday and Tuesday of next week, Press TV said.