The attack caused minor injuries to a soldier at the joint Army-RUC base in the south Armagh town, which is currently undergoing extensive renovations following damage caused by previous explosions.
Mr Adams was speaking after a day of widespread questioning of Sinn Fein's and the IRA's professed commitment to a peace process following the IRA killings of two Protestants in Co Londonderry on Sunday. The keynote was struck by Cardinal Cahal Daly, the Catholic Primate of all-Ireland, who described the killings as morally outrageous, inexcusable and senseless.
The deaths overshadowed yesterday's Anglo-Irish intergovernmental meeting in Belfast, which was co-chaired by the Secretary of State for Northern Ireland, Sir Patrick Mayhew, and the Irish foreign minister, Dick Spring.
The two men died when gunmen opened fire on their car in the village of Garvagh. They have been named as Alan Smith, 40, and John McCloy, 28. Mr Smith, a former member of the Ulster Defence Regiment, survived a previous attempt on his life when a bomb exploded under his van last March.
The IRA claimed the men were members of the Ulster Defence Association, but this was denied by their families, by security sources and by the UDA itself. RUC sources indicated the shootings may have been a case of mistaken identity.
Speaking after yesterday's meeting in Belfast, Dick Spring said he still hoped that those who espoused violence would realise sooner rather than later that they would not achieve their aims by force. Both he and Sir Patrick said work was going on behind the scenes to pave the way for inter-party talks, though Irish sources left the clear impression that little political movement was likely in advance of the European elections in June.
Mr Adams's warning, meanwhile, was accompanied by his now- familiar calls on the British government to show more flexibility. His use of the word 'crisis' was new, however, and may signal his fear that the peace process, which has clearly lost momentum, might be in real danger of going off the rails completely. The Garvagh shootings represent a significant widening of the IRA net. Loyalist violence has also increased appreciably in recent weeks, awakening fears that a serious escalation is on the cards.