Iranian Foreign Minister Abbas Araghchi blamed the US for Iran's Monday night attack in the Strait of Hormuz.
"Clause 13 of the Memorandum of Understanding is clear: Negotiations on a final agreement will not begin as long as the threats continue. Honor your signature," Araghchi said Tuesday morning.
In the Monday night attack, the Iranian Revolutionary Guards Corps (IRGC) attacked at least one LNG tanker as it was transiting the Strait of Hormuz.
A report broadcast on Iranian state television claimed that the strike against the vessel was carried out after the tanker ignored warnings issued to it by Iranian forces stationed in the area.
The US twice recently struck Iranian targets in the Strait of Hormuz in response to Iranian violations of the ceasefire.
President Donald Trump subsequently warned that the US may be forced to “militarily complete the job" if Iran continued to violate the ceasefire.