Martin McGuinness, Northern Ireland's education minister, has admitted that at the time of Bloody Sunday in 1972 shootings he was second in command of the provisional IRA's Derry unit.

In a press conference on Wednesday afternoon McGuinness responded to recent press speculation over his statement to the Bloody Sunday tribunal. He said that he had given a draft statement to tribunal lawyers and would be in discussion with them over coming weeks. He would give evidence when asked to do so, he confirmed.

"I will definitively tell the tribunal that the IRA did not engage the British army on Bloody Sunday," said McGuinness.

He added "I have given a very full, very frank and very honest account of what I was doing on Bloody Sunday." He confirmed his statement would say he was second in command at the time of the shootings. However he failed to give a direct answer to questions about when he may have left the IRA.

McGuinness went on to say the focus should remain on the killing of civilians by the army, not his personal role. It would be a "serious blunder" for anyone to make him the focus of the inquiry.

He also criticised those Unionists who would take any opportunity to undermine the Good Friday Agreement. However, he welcomed the reaction of "sensible" elements within Unionism who recognised he was making "a positive contribution".

Reports of McGuinness' admission to the inquiry had led the Democratic Unionists to call for his arrest for IRA membership.

Press reports indicated that McGuinness' statement to the inquiry would say that the IRA were asked to support a peaceful march and accepted the proposal. At a meeting the day before the march with the IRA's commanding officer it was agreed that members of the IRA would not engage with the security forces.

It is believed McGuinness will also say that two IRA units were armed and told to stay in the Creggan and Brandywell areas while all other members were given the choice of attending the march or spending the day with their families.

The civil rights demonstration on Sunday January 30, 1972, resulted in the shooting of 13 civilians, with another man dying later from his injuries, by British paratroopers.

Although the inquiry has received evidence from a security service agent that McGuinness fired the first shot, he has dismissed this as untrue.