BAGHDAD (AFP) - The United States released dozens of Iraqi prisoners on Tuesday, an official said, in what is a key part of the security agreement that will eventually see American troops leave the country. "Approximately 70 detainees were released today, and we'll average 50 a day," a US military spokesman told AFP. The prisoner releases were due to start on Sunday but were delayed because of security issues surrounding provincial elections that took place across Iraq the previous day. The releases form part of the security accord signed in November by Baghdad and Washington that calls for the withdrawal of US troops from Iraq by the end of 2011 and handover of security responsibilities to the Iraqis. Under the agreement, prisoners must either be set free or handed over to the Iraqi authorities. "These are fair releases " not mass releases " of those detainees who the US and the government of Iraq think no longer pose a threat to the security or stability of Iraq," said Brigadier General David Quantock. "We are working very hard with the Iraqi government to ensure the releases are conducted in a safe and orderly manner," he added.The coalition currently has about 15,000 prisoners in custody, the military said Tuesday.