Iran on Thursday rejected US accusations that the Iranian shipping company IRISL was involved in Tehran's alleged nuclear weapons programme, the official news agency IRNA reported.

"This US claim is like other allegations that independent countries are being accused of, without providing any evidence," the state shipping company said in a statement.

The United States said on Wednesday it would slap sanctions on the Islamic Republic of Iran Shipping Lines and 18 other affiliated entities for providing logistical services to Iran's Ministry of Defense and Armed Forces Logistics.

"Not only does IRISL facilitate the transport of cargo for UN designated proliferators, it also falsifies documents and uses deceptive schemes to shroud its involvement in illicit commerce," said Stuart Levey, Under Secretary for Terrorism and Financial Intelligence, in a statement.

"IRISL's actions are part of a broader pattern of deception and fabrication that Iran uses to advance its nuclear and missile programs," he said.

IRISL said allegations that it was transporting military cargo was a baseless claim.

"Documents issued by the Islamic republic shipping company are completely substantiated and the company does not issue falsified and forged papers as the US government claims," the statement said.

The shipping company stressed that it was a "private stock company with thousands of shareholders that carries out its economic activities completely according to international rules and regulations."

It said that US sanctions "will not have any effect on the activity of the IRISL or the traffic of this company's ships in international waters and ports."

"The Islamic republic's shipping company will pursue the US government's accusations via international institutions," it added.

Washington accuses Iran of seeking to develp atomic weapons, an allegation vehemently denied by Tehran.