Iraq has signed a contract with Italy's Trevi Group worth 273 million euros ($296 million) to reinforce and maintain the Mosul hydro-electric dam for a period of 18 months, state television reported on Wednesday.

Italy has said it plans to send 450 troops to protect the site of dam, which is 3.6 km (2.2 miles) long and close to territory held by Islamic State militants in the country's north. The Italian foreign ministry confirmed that the contract had been signed.

The agreement followed talks in New York between Italian Foreign Minister Paolo Gentiloni and U.S. and Iraqi officials, the ministry said in a statement.

Mosul dam has suffered from structural flaws since its construction in the 1980s and a collapse would unleash a wall of water down the heavily populated Tigris River valley.

The Iraqi government says it is taking precautions against such a scenario but has sought to play down the risk, with Prime Minister Haider al-Abadi on Sunday describing the likelihood of a breach as "extremely small".

Islamic State militants seized the dam in August 2014, raising fears they might blow it up and send a huge wave on to Mosul and other downstream cities including Baghdad which could kill hundreds of thousands of people.

The dam was recaptured two weeks later by Iraqi government forces backed by U.S.-led coalition air strikes, but the United States has said that disruption of maintenance operations has increased the likelihood of a breach.