An Iranian warship fired on a Romanian oil rig off the coast of Iran on Tuesday, and troops from the vessel boarded and occupied the rig, the rig's owner said. Sergiu Medar, a national security adviser to President Traian Basescu, said the incident stemmed from a commercial dispute Iran is treating "in an extreme way." He gave no details of the dispute. The Foreign Ministry said it had summoned the Iranian ambassador to provide details about the incident, and that it planned to send an embassy team to the area and it called on Iranians authorities to immediately free Romanian crew members being held by the troops who occupied the rig. "We are dealing with a commercial dispute that is being treated in an extreme way by the Iranian authorities," Medar told Realitatea TV. He added that Iranian authorities had not confirmed the incident. But at the Romanian Embassy in Tehran, political consul Yujin Chira did confirm it. He provided few details. "Some forces opened fire. That an incident has happened is true. We have no details or the reason yet," he said. Radu Petrescu, spokesman for GSP, said the Iranians first fired into the air and then fired at the Orizont rig. Half an hour later, troops from the ship boarded and occupied the rig, and the company soon lost contact with the 26 crew members, he said. Petrescu said he had no information about any injuries or deaths. The Orizont rig has been moored near Kish island in the Persian Gulf since October, he told The Associated Press. Gabriel Comanescu, GSP president, said, "They fired on the rig. They destroyed one of the cranes. Four armed soldiers climbed aboard the rig." Realitatea TV reported that 20 Romanian crew members and seven Indians were on the rig. Romania's charge d'affaires in Iran, Mircea Has, said the Romanian crew members were not injured, but that they were being detained on the rig's helicopter pad. A Romanian lawmaker who leads the left-wing opposition accused Iran of taking a hostile action against Romania. He called on President Basescu to lead an emergency meeting of the country's supreme defense council. "The oil rig Orizont is Romanian territory," said Mircea Geoana, who heads the Social Democratic Party. Geoana served as foreign minister during 2000-2004. GSP, also known as the Oil Services Group, is a private Romanian company established in 2004, which operates six offshore rigs that it bought from Romania's largest oil company, Petrom. Two of its rigs are operating near the Iranian coast in the Gulf as part of a deal signed between Petrom, GSP and Dubai-based Oriental Oil Co. GSP was in Iranian courts earlier this year over a dispute involving another oil rig, Fortuna, the financial weekly Saptamana Financiara has reported. It was unclear whether Tuesday's incident was related to legal issues. The Orizont rig was built in 1987 and weighs 13,000 tons. Kish, in the southern end of the Persian Gulf, houses the offices of about 100 Iranian and foreign oil companies.