In most cases reimbursement would be required.

in depth

"We are currently working out the particular modalities of delivering the offered assistance," the State Department said, adding that details would be "forthcoming once these arrangements are complete."

The ongoing oil spill - the worst in US history – began in April following an explosion on the BP-operated Deepwater Horizon oil rig, which left 11 workers dead.

Since then an estimated 1.6 million to 3.6 million barrels of oil have already poured into the Gulf from the ruptured undersea wellhead, fouling large stretches of US coastline, killing wildlife and devastating coastal fishing communities.

Skimmers

A US Coast Guard agency coordinating the response to the spill with BP said international offers of floating boom equipment to contain the oil and collect it off the surface of the water had been accepted from Canada, Mexico, Norway and Japan.

Clean up efforts have been suspended due to an approaching storm [AFP]

Gina Ruoti, spokeswoman from the Unified Area Command, told the AFP news agency that in addition skimmers had been accepted from Mexico, Norway, France and Japan and a sweeping arm system has been accepted from the Netherlands.

Non-material offers of assistance had also come from the European Union and International Maritime Organization, she added, without detailing how much the assistance would be.

The announcement of international assistance in containing the disaster came as some clean-up efforts were halted on Tuesday with the approach of the first hurricane of the 2010 Atlantic storm season.

The US National Hurricane Center said Tropical Storm Alex had intensified into a hurricane late on Tuesday as it moved over southern Gulf waters.

Controlled burns of oil on the ocean, flights spraying dispersant chemicals and booming operations were all stopped as the storm approached.

Officials from BP said the storm was not expected to damage oil capture systems that engineers have placed over the ruptured well, or interrupt the company's plans to drill a pair of relief wells intended to plug the leak by August.

However waves as high as 4 metres would delay plans to hook up a third system intended to capture more of the leaking oil.