The leaders of Northern Ireland’s two largest parties reached a deal on Tuesday to preserve the power-sharing agreement that has kept the peace in the province for two decades.

The breakthrough came after ten weeks of negotiation with the governments of Ireland and the United Kingdom.

British prime minister David Cameron hailed the deal as “an important turning point for Northern Ireland.” Peter Robinson, the leader of the largest unionist party in the territory, said it would “consolidate the peace, secure stability, enable progress and offer all our people hope for the future.”

Robinson withdrew his ministers from Northern Ireland’s executive in September amid a row with the region’s largest Irish nationalist party, Sinn Féin.

The crisis started a month earlier when a former Irish Republican Army gunman was shot dead, apparently in retaliation by members of the same paramilitary organization that fought against British rule in Northern Ireland for decades.

The IRA was supposed to have disbanded under the 1998 Good Friday Agreement that ended the armed struggle in Northern Ireland and established its devolved assembly and executive.

Sinn Féin, the political wing of the republican movement, denied any role in the August murder and accused the mostly Protestant unionists of creating a “fake crisis.”

Mistrust between the both sides remains. Tuesday’s agreement does not address thorny issues from the past.

It does entail extra welfare spending for Northern Ireland and would allow the region to cut its corporate tax rate to 12.5 percent by 2018 to better compete with mainland Ireland.

Smaller parties were skeptical of the agreement which they saw a stitch-up between their two bigger rivals. Both the more centrist Ulster Unionist Party — which withdrew from the devolved government before Robinson’s more right-wing Democratic Unionist Party did — and the relatively moderate nationalist Social Democratic and Labour Party had yet to say whether they supported the deal.