Adds details, background, writes through

By Katya Golubkova and Kantaro Komiya

TOKYO, April 28 (Reuters) - A Panama-flagged tanker, Idemitsu Maru, carrying crude oil from Saudi Arabia is attempting to cross the Strait of Hormuz, shipping data showed on Tuesday.

The very large crude carrier (VLCC) is managed by Idemitsu Tanker Co, a unit of Japanese refiner Idemitsu Kosan 5019.T, and is carrying around 2 million barrels of Saudi crude, according to LSEG ship-tracking data.

The vessel was about 30 kilometres (18.6 miles) east of Larak Island and moving eastward with its Automatic Identification System active, separate data from MarineTraffic showed.

Idemitsu Kosan declined to comment on individual ships.

Japan has recently stepped up diplomatic efforts to secure the energy supply, disrupted by the U.S.-Israeli war with Iran, which broke out in late February.

In a phone call last week, Prime Minister Sanae Takaichi asked Saudi Arabia's Crown Prince Mohammed bin Salman to expand supplies to Japan, and her industry minister, Ryosei Akazawa, has been speaking to other senior Gulf officials as well.

Before the Iran war disrupted Middle East crude oil and liquefied natural gas supplies, Japan was relying on the region for around 95% of its oil imports with the bulk coming via the Strait of Hormuz.

Earlier in April, the Sohar LNG tanker co-owned by Japan's Mitsui O.S.K. Lines 9104.T and the Mitsui-owned LPG tanker 8031.T, Green Sanvi, crossed the strait.