HANOI (Reuters) - Companies from Iran, Israel, China, Russia and the United States will showcase military equipment at an arms expo in Hanoi in December, Vietnam's defence ministry said on Tuesday, a rare case of geopolitical rivals exhibiting their wares together.

Communist-run Vietnam has for years been seeking to diversify its military supplies to reduce its decade-long reliance on Russia, and has discussed potential procurement deals with multiple countries trying to leverage its flexible diplomacy of good relations with great powers.

At the defence expo to be held in the capital Hanoi on Dec. 19-22, nearly 200 companies from 27 countries have already reserved booths, the ministry said in a statement, including firms from China and Iran, which had not attended Vietnam's first international military fair in 2022.

The expo will bring together defence companies from Israel and Iran, who have launched missile attacks and airstrikes on each other in the past year. Iran will attend even though it is subject to sweeping Western sanctions.

At the past edition in 2022, Israeli defence firms Elbit Systems and Rafael Advanced Defense Systems were among the exhibitors.

Vietnam's defence ministry has not released yet a full list of participants and it is not clear what arms will be displayed. Companies at times showcase only models of their bigger weapons.

China's state-owned defence giant Norinco Group, which is subject to U.S. sanctions, will attend, Le Quang Tuyen, deputy head of the defence industry department, said on the sidelines of a press conference about the expo on Tuesday.

In the same large exhibition area in a military airport in the outskirts of Hanoi, U.S. companies Boeing ( BA ) and Lockheed Martin ( LMT ) will also have their booths, Tuyen added.

Lockheed Martin ( LMT ) is in advanced talks with Vietnam for the supply of a handful of C-130 Hercules military transport planes, a senior U.S. official said earlier this month, confirming an earlier Reuters report.

A company spokesperson did not immediately reply to a request for comment on the matter.

The variegated list of attendees is "bamboo diplomacy on show," said Nguyen The Phuong, an expert on Vietnamese security at Australia's University of New South Wales, using a popular definition for Vietnam's flexible foreign policy.

"Vietnam will play with any partner it sees fit, particularly in defence," he said.

The country also intends to use the fair to strengthen cooperation with foreign partners to boost its growing domestic industry with tech transfers and "seek opportunities to export," the defence ministry said.

At the 2022 expo, Vietnam signed five contracts with foreign defence firms, Tuyen said, although there is no public record for them.

(This story has been refiled to correct the spelling of Israel in the headline)