Concerns are growing among Japanese energy and shipping companies over the situation in the Middle East following Thursday’s attacks on two tankers near the Strait of Hormuz.

The attacks on the tankers, including one operated by a Japanese shipping company, “have had no immediate impact on crude oil supply,” said an official of oil wholesaler Idemitsu Kosan Co.

As of the end of May, Japan had crude oil reserves equivalent to over 200 days worth of consumption in total in the public and private sectors.

Crude oil prices stabilized after shooting up following the attacks. Gasoline prices in Japan are “unlikely to rise immediately,” a Japanese oil industry source said.

Japan imports about 80 percent of its oil and some 30 percent of its natural gas through the Strait of Hormuz. The waterway is “a lifeline to Japan,” a senior industry ministry official said.

Japanese energy-related companies are collecting information as they brace for a potential situation in which the Middle East will remain unstable over a long period.

“We expect anything may happen,” Satoru Katsuno, chairman of the Federation of Electric Power Companies of Japan, told a news conference Friday.

“We’ll pay close attention to future developments with a sense of crisis and manage risk” with the possibility of a closure of the strait in mind, said Katsuno, who is also the president of Chubu Electric Power Co.

Major Japanese shipping firms have taken steps including increasing the number of personnel on lookout aboard ships, as well as ensuring full-speed operations of vessels in waters near the sites of the attacks.

“There is nothing more we can do,” said a public relations official at Mitsui O.S.K. Lines Ltd.

“We’ll have to reconsider operating ships in that sea area if the danger increases further,” an official of another major shipping firm said.