DUBAI/LONDON - Targeted Western sanctions are hurting Iran's vital shipping industry and if the pressure continues its biggest cargo carrier will face increasingly grave problems, the head of the Iranian line said.

Many of Iran's imports, including food and consumer goods, arrive on container, bulker and other ships, but the number of vessels calling at its ports has dived by more than half this year as the United States and European Union tighten the screws.

"If the government was not assisting, (sanctions) would have stopped a lot more of our activity," Mohammad Hussein Dajmar, managing director of the Islamic Republic of Iran Shipping Lines (IRISL), said in an interview published on Sunday.

"If this situation continues, certainly our operations will face serious problems. Shipping has been among the primary objectives of sanctions. The damage has had a significant bearing. More pressure will result in greater damage," Dajmar was quoted as saying by Iranian business daily Jahan-e Sanat.

Executives of other Iranian shipping companies such as the National Iranian Tanker Company have been less willing than Dajmar to speak about the impact of sanctions.

IRISL, has been on a Western blacklist of sanctioned entities for years accused of transporting weapons, which it denies.

IRISL targeted by cyber attack

Dajmar said IRISL suffered a cyber attack in August 2011.

"The attack was heavy and showed that they (the attackers) were being supported by powerful sources," he said. "There was considerable damage. A lot of pressure was imposed on us," he added.

IRISL has tried to dodge sanctions by changing its flags and setting up front companies, the US Treasury and the European Union have said. It remains easy to track a vessel as it keeps a unique International Maritime Organization (IMO) number.

"We cannot access European waters through changing flags, so we do not take the risk," Dajmar said.

"The IMO numbers are fixed and finding out who owns a ship is not a complicated task.... The United Nations has not barred the activity of our ships, this is only from the US and Europe."

Dajmar said out of its fleet of 165 ships, 20 were currently laid up and not trading.

While broader Western sanctions are directed chiefly against Iran's nuclear program, which is suspected of having a military goal, IRISL has been pinpointed because of suspicions that it transports weapons for Tehran.

Dajmar said IRISL did not work for any Iranian military agencies. "It's been years that we do not work with them. They don't have such large needs and any needs that they do have they produce domestically," he said.

"It's not like during the war years when the amount of weapons was large and to move them they used ships," he added, referring to the conflict with Iraq in the 1980s.

As part of the trade restrictions the European Union has put an embargo on ship insurance provision, which forced IRISL to switch to Iranian insurance providers.

"Using such (European) insurers was much more profitable and after losing them, we had to set up domestic insurers," he said.

"We are now in a war. They wanted to force us to fall down but they didn't succeed. Today, in global markets we lose markets and the world is putting limitations on us. We will continue even if there is only one country working with us."

President Mahmoud Ahmadinejad has faced growing criticism over his handling of the economy, especially after Iran's rial currency plunged by more than a third in recent weeks.

Dajmar was quoted earlier this month as saying Iran's central bank had blocked $50 million of the company's assets - reflecting the acute shortage of US currency.

"A few years ago our profit was about $500 million. The company has a strong base but if this situation continues our activities will definitely face problems," he told the daily.

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