The confrontation between Iran and the United States is expected to escalate on Thursday as Iran warned it is ready to violate its commitments to the 2015 nuclear deal for the first time.

Iran has said it will accumulate enough low-enriched uranium to breach the 300 kilogram limit set in the 2015 nuclear deal unless European countries find a way to help it side-step US sanctions.

It said earlier this month that it expects to reach that level on Thursday.

Majid Takht Ravanchi, Iran's ambassador to the United Nations, told the Security Council on Wednesday evening that US actions had "rendered the JCPOA almost fully ineffective, and that "Iran alone cannot, shall not and will not take all of the burdens" to preserve it.

The deadline comes after the two country's leaders both promised they would not back down in a confrontation that has led them to the brink of war.