Germany's Germanischer Lloyd (GL) has stopped verifying safety and environmental standards for Iran's biggest shipping companies, a letter from the company showed, the last big European classification society to pull back as sanctions heat up, Reuters reported.
Without verification from such bodies, ships are unable to call at international ports.
The move follows similar decisions in recent weeks by British classification society Lloyd's Register, France's Bureau Veritas and Norway's Det Norske Veritas to halt operations in Iran as Western powers pile pressure on the Islamic Republic over its disputed nuclear program, putting companies that still trade with Iran in the firing line.
Classification societies are hired by ship owners to regularly check that vessels, from their hull and propulsion systems to the machinery and appliances, meet international safety standards. Under international conventions, a classification is required for a ship to dock at major ports.
World powers began two days of talks with Iran on Monday to try to end a decade-long stand-off over Tehran's atomic work and avert the threat of a new war in the Middle East.
Western countries suspect Iran's atomic work is aimed at developing arms, while Tehran says its program is for peaceful purposes.
UANI, which includes former U.S. ambassadors on its board and is funded by private donations, had said GL's cover for IRISL was in violation of EU sanctions. UANI, which seeks to prevent Iran getting nuclear weapons, had also pressured Bureau Veritas before the French firm stopped its Iran cover.
IRISL has been on a Western blacklist of sanctioned entities for a number of years, while NITC faces the prospect of potential sanctions after the U.S. senate passed a bill last month that aims to target Iran's biggest tanker operator.
GL said it had always been fully compliant with EU and German requirements and had pursued a "very diligent and careful policy" in relation to its activities with Iranian firms.
There are more than 50 agencies that classify vessels, but not all are members of the International Association of Classification Societies, which classifies more than 90 percent of the world's merchant fleet and includes GL, Bureau Veritas, Lloyd's Register and Det Norske Veritas.
It is likely that Iran is already securing cover from Asia-based classification societies, shipping industry sources said.
Edited by: S. Isayev