Backgrounder: Three rounds of indirect Iran-U.S. nuclear talks

The United States has begun "major combat operations" in Iran, U.S. President Donald Trump said on Saturday, hours after Israel launched a "preemptive" strike against the country. 

Iran closed its airspace while the attack was ongoing.

The military escalation follows three rounds of indirect talks between Washington and Tehran. 

Here is a timeline of those diplomatic engagements.

February 6, Muscat, Oman

The U.S. and Iran held first round of indirect talks in Muscat, Oman, mediated by Omani Foreign Minister Sayyid Badr bin Hamad bin Hamood Albusaidi.

U.S.: Trump described the discussions as "very good" and said the two sides would meet again soon, while cautioning that "we have to see what that deal is." He warned that failure to reach a nuclear agreement would carry "very steep consequences."

Iran: Iranian Foreign Minister Seyed Abbas Araghchi described the meeting as a "good start" conducted in a "positive atmosphere." He emphasized that discussions were strictly limited to nuclear issues and did not cover broader regional files.

February 17, Geneva, Switzerland

The U.S. and Iran held second round of indirect nuclear talks at Oman's embassy in Geneva, Switzerland, still mediated by the Omani foreign minister.

U.S.: The United States described the second round as held in a "constructive atmosphere," noting that discussions covered technical issues related to Iran's nuclear program. Officials stated that progress was made in clarifying positions and identifying shared objectives, and that draft frameworks for a potential agreement would be prepared. Washington emphasized that diplomacy remains the preferred path, while firmly maintaining red lines regarding Iran's nuclear capabilities.

Iran: Araghchi said the talks were "more substantive" than the previous round and that the two sides reached a general understanding on guiding principles for future negotiations. He stressed that discussions were strictly limited to nuclear issues, must proceed without pressure, and that progress requires reciprocity and sanctions relief.

February 26, Geneva, Switzerland

The U.S. and Iran held third round of indirect nuclear talks at Oman's embassy in Geneva, Switzerland, still mediated by the Omani foreign minister. No agreement was reached during the negotiations, but all parties gave positive assessments and announced plans to continue technical discussions in Vienna, the capital of Austria, on March 2.

U.S: Trump said on Friday that he is "not happy" about the progress of negotiations with Iran. He emphasized that he does not want to use force but said sometimes "you have to."

Iran: Araghchi told Iran's state TV that the talks "made very good progress and entered into the elements of an agreement very seriously, both in the nuclear field and in the sanctions field," according to media reports. He added that the two sides may hold a new round of talks within a week.