The Sinn Fein president, who played a leading role in the peace process in the troubled British province, was arrested last night over the killing of mother-of-ten Jean McConville in 1972.
Adams, 65, strongly denied involvement in one of the most infamous incidents of the so-called Troubles in Northern Ireland, and questioned the timing of the arrest before local and European elections.
"While I have never disassociated myself from the IRA and I never will, I am innocent of any part in the abduction, killing or burial of Mrs McConville," Adams said.
McConville, 37, was snatched from her home in west Belfast in front of her screaming children, becoming one of more than a dozen so-called "disappeared" of the conflict. Her body was found, shot in the back of the head, in 2003.
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The party now shares power with its old foe, the pro-British Democratic Unionist Party (DUP), in a devolved government in Belfast, and Sinn Fein member Martin McGuinness is deputy first minister.
The arrest was a "deliberate attempt to influence the outcome of the elections in three weeks time", said McGuinness.
The British and Irish governments, which worked together on the 1998 Good Friday peace accords that largely ended the violence, tried to calm rising tensions.
"There has been absolutely no political interference in this issue," British Prime Minister David Cameron said.
His Irish counterpart, Enda Kenny, added: "All I can say is that I hope the president of Sinn Fein answers in the best way he can, to the fullest extent that he can, questions that are being asked about a live murder investigation."
"It would be political policing if the police had information and didn't follow it up because of the political profile of an individual," Robinson said.