His comments, made to British and Irish parliamentarians in Dublin, represent the Irish government's strongest demand yet for the IRA and Sinn Fein to match their talk of peace with action.
The recent rise in killings have caused many observers North and South to wonder whether the Irish peace process may be unravelling. The IRA, which had been confining its attacks to the security forces, has returned to killing Protestants and an alleged drug-dealer.
This republican escalation has not taken place in a vacuum, since loyalist assassins have also been increasingly active. The net result has been a widespread apprehension that, after a relative lull in the killings, Northern Ireland may be drifting back to the bad old days.
Yesterday in a shopping centre in Glengormley on the outskirts of north Belfast, gunmen from the Irish National Liberation Organisation shot dead one Protestant man and seriously injured another. This may have been retaliation for Tuesday night's killing of a Catholic in the New Lodge district of north Belfast. Joe McCloskey, 52, a father of six, was killed by gunmen who walked into his living-room and shot him.
In his speech Mr Reynolds condemned loyalist violence but reserved most of his criticism for republicans. He declared: 'Sinn Fein leaders have claimed that the achievement of peace is the total priority of their organisation. How do they expect this to be believed by the public when they see republican violence on the rise again?
'What does the murder of two Protestants and several policemen this year contribute to moving the peace process forward?' He continued: 'How can we be confident of the good faith of the republican movement when members engage with increasing frequency in murder? Are these events a sign that the unity of purpose and discipline in that organisation is not as strong as is often supposed? Do they in fact have the ability and the coherence to agree to peace? Answers are demanded by the Irish people.'
A 23-year-old Royal Marine appeared in court in Belfast yesterday on five terrorist charges. Derek William Adgey was accused of conspiring to murder a prominent republican, Brian Gillen, and others.
Six men accused of being involved in a plot to buy bomb parts and other weapons which were to be smuggled from the United States to the IRA have been acquitted by a jury in Tucson, Arizona.
The men - who include three from Northern Ireland and became known to Irish sympathisers as the 'Arizona Six' - were charged with illegally purchasing 2,900 explosive detonators from a company in Arizona under the pretext that they were to be used for mining. The devices were packed in boxes marked as clothing, and smuggled to New York on a Greyhound bus, the prosecution alleged. It also claimed that some of the devices were secretly transported to Northern Ireland, via Canada, and used in bombings between January 1991 and June 1992.
One man was believed dead and another injured following a shooting in Springfield Park, west Belfast, last night.