LONDON (Reuters) - The U.S. is seeking to hire a merchant ship to deliver hundreds of tons of arms to Israel from Greece later this month, tender documents seen by Reuters show.

The U.S. Navy’s Military Sealift Command (MSC) said the ship was to carry 325 standard 20-foot containers of what is listed as “ammunition” on two separate journeys from the Greek port of Astakos to the Israeli port of Ashdod in mid-to-late January.

A “hazardous material” designation on the manifest mentions explosive substances and detonators, but no other details were given.

“Shipping 3,000-odd tons of ammunition in one go is a lot,” one broker said, on condition of anonymity.

“This (kind of request) is pretty rare and we haven’t seen much of it quoted in the market over the years,” he added.

The U.S. Defense Department, contacted by Reuters on Friday in Washington, had no immediate comment.

The MSC transports amour and military supplies for the U.S. armed forces aboard its own fleet, but regularly hires merchant ships if logistics so require.

The request for the ship was made on December 31, with the first leg of the charter to arrive no later than January 25 and the second at the end of the month.

The tender for the vessel follows the hiring of a commercial ship to carry a much larger consignment of ordnance in December from the United States to Israel ahead of air strikes in the Gaza Strip.

A German shipping firm which won that tender confirmed the order when contacted by Reuters but declined to comment further.

CHARTERS “RARE”

Shipping brokers in London who have specialized in moving arms for the British and U.S. military in the past said such ship charters to Israel were rare.

Israel is one of America’s closest allies and both nations regularly sell arms to each other.

A senior military analyst in London who declined to be named said that, because of the timing, the shipments could be “irregular” and linked to the Gaza offensive.

The ship hired by the MSC in December was for a much larger cargo of arms, tender documents showed.

That stipulated a ship to be chartered for 42 days capable of carrying 989 standard 20-foot containers from Sunny Point, North Carolina to Ashdod.

The tender document said the vessel had to be capable of “carrying 5.8 million pounds (2.6 million kg) of net explosive weight,” which specialist brokers said was a very large quantity.

The ship was requested early last month to load on December 15.

In September, the U.S. Congress approved the sale of 1,000 bunker-buster missiles to Israel. The GPS-guided GBU-39 is said to be one of the most accurate bombs in the world.

The Jerusalem Post, citing defense officials, reported last week that a first shipment of the missiles had arrived in early December and they were used in penetrating Hamas’s underground rocket launcher sites.