Several American diplomats, along with Israeli and Saudi Arabian officials, were reportedly on a hit list linked to an ongoing assassination campaign by Iranian intelligence.
The U.S. officials targeted in the alleged plot were stationed at the American embassy in Azerbaijan, according to reports in The Washington Post. The central Asian country shares its southern border with Iran.
Alleged Iranian conspirators also schemed to kill embassy members with a car bomb, according to the Post.
The investigation by American and foreign intelligence into the planned attacks has uncovered evidence tying the plot to Iranian-backed terror group Hezbollah and other smaller factions working inside Iran.
The plan was to kill U.S. and foreign diplomats over a 13-month period and was only uncovered after Azerbaijani authorities rounded up more than 20 alleged co-conspirators in arrests this year.
News of the planned assassinations comes shortly after Tehran and members of the P5+1 group —representatives from all five countries on the UN Security Council plus Germany — concluded talks on Iran's nuclear program.
During the talks, held in Baghdad last week, negotiators discussed Iran's nuclear ambitions and whether those ambitions included building a nuclear bomb.
Iran has denied any claims that it is pursuing a nuclear weapon. However, Tehran continues to keep the program shrouded in secrecy.
Iranian officials have also accused Israel and the United States of carrying out its own assassination campaign against senior officials working on the country's nuclear program.
At the end of the Baghdad talks, both sides agreed to meet again in Russia in June to continue negotiations.
In 2011, American intelligence officials were able to foil an Iranian plot to kill the Saudi Arabia's ambassador to the United States during a visit to Washington.
Iranian agents reportedly made contact with members of Los Zetas, a violent drug cartel operating in Northern Mexico, to carry out the hit.