Moreover, despite the Dáil's acceptance of the Anglo-Irish Treaty in January 1922, which confirmed the future existence of Northern Ireland, there were clashes between the IRA and British forces along the new border from early 1922. In part, this reflected Michael Collins' view that the Treaty was a tactical move, or "stepping stone", rather than a final settlement. A number of IRA men were arrested in Derry when they travelled there as part of the Monaghan Gaelic football team. In retaliation, Michael Collins had forty-two loyalists taken hostage in Fermanagh and Tyrone. Right after this incident, a group of B-Specials were confronted by an IRA unit at Clones in Southern territory, who demanded that they surrender. The IRA unit's leader was shot dead and a gun battle broke out, in which four Special Constables were killed. The withdrawal of British troops from Ireland was temporarily suspended as a result of this event. Despite the setting up of a Border Commission to mediate between the two sides in late February, the IRA raided three British barracks along the border in March. All of these actions provoked retaliatory killings in Belfast. In the two days after the Fermanagh kidnappings, 30 people lost their lives in the city, including four Catholic children and two women who were killed by a Loyalist bomb on Weaver Street. In March, 60 died in Belfast, including six members of the Catholic McMahon family, who were targeted for assassination by members of the Special Constabulary in revenge for the IRA killing of two policemen (See McMahon murders). In April, another 30 people died in the Northern capital, including another so called 'uniform attack', the Arnon Street massacre, when six Catholics were killed by uniformed policemen.