TEHRAN -- Iran's Foreign Ministry Spokesman Abbas Mousavi said on Wednesday that the country keeps its door open to diplomacy and talks over its nuclear issue, Press TV reported.

Iran remains committed to the 2015 nuclear deal, officially known as the Joint Comprehensive Plan of Action (JCPOA), but at the same time defends the nation's rights, Mousavi was quoted as saying by Press TV.

Tehran is not seeking tensions over its nuclear issue, he said, adding that the European countries should address "the root cause of the tensions" if they really seek to calm the situation.

He suggested the US policies vis-a-vis Iran as the major cause of problem behind the nuclear issue.

"The illegal and unilateral withdrawal from the nuclear agreement followed by extensive sanctions are examples of the US measures against Iran, which is an economic terrorism and economic war," Mousavi added.

Iran announced on Monday that it has raised the concentration of its enriched uranium to 4.5 percent from 3.67 purity, a limit set by the nuclear agreement for Iran's enrichment concentration.

Iran will aim at production of 20 percent uranium enrichment in the next step if the signatories to the 2015 nuclear deal do not help Iran benefit from the economic privileges of the deal, Behrooz Kamalvandi, spokesman for Atomic Energy Organization of Iran, said on Monday.

Iran said earlier that it will reduce its commitments to the deal unless the parties to the accord take "practical and concrete" measures to counter the anti-Iran economic sanctions of the United States after the latter's unilateral exit from the deal in May 2018.