CAIRO (Kyodo) A group of firms led by Nippon Oil Corp. has agreed in principle with Baghdad to obtain the right to develop an oil field in Iraq in what would be the biggest deal of its kind for Japanese companies, sources close to the negotiations said.

The move comes as Iraq, which has the world's third-largest proven crude oil reserves, is trying to attract foreign investment in a process seen as crucial to the country's future.

The agreement indicates the Japanese group has outstripped Eni S.p.A, an Italian energy firm that is also in talks with the Iraqi government for development rights in the southern city of Nasiriyah.