BRUSSELS - Dutch-speaking and francophone parties reached a major breakthrough Thursday in the world's longest negotiations to form a new governing coalition a record 15 months after elections were held.

The eight parties announced they had reached a deal on the breakup of an electoral district in and around bilingual Brussels, an issue that had vexed politicians for almost half a century and was at the heart of the long standoff between the linguistic groups as they sought to reform the constitution.

The parties said in a statement that negotiations on other issues, such as economic and social policy, would continue later Thursday.

"Our work is far from over, and we still need a lot of negotiations," said the joint statement.

Still, after a government stalemate already considered by far a world record, news of the breakthrough was lauded by many as fundamental.

"It is a historic breakthrough. It is extremely important and positive," said caretaker Prime Minister Yves Leterme.

"We have crossed a difficult bridge," said Joelle Milquet, the head of the Francophone CdH party.

Over the past months, politicians have increasingly started worrying about the pressure of financial markets doubtful about the long-term future of the country.

Leterme took as many social and economic decisions as his remit allowed but negotiators realized drastic action had to be taken, especially after Leterme announced early this week he would leave his post at the end of the year at the latest and move to the Paris-based Organization for Economic Cooperation and Development.

The June 13, 2010, elections brought the Dutch-speaking separatist N-VA party to the fore, and at first it was including in the protracted negotiations.

But when no compromise could be found, the traditional parties that have dominated Belgian politics for years decided to try it on their own in July.

By that time it had swept past the year-mark -- and countries like Iraq and Cambodia -- for the unofficial title as longest government negotiations.

The insistence on more self-rule in northern Belgium for its 6 million Dutch-speaking Flemings was always central in negotiations. The parties representing the 5 million francophones living in southern Wallonia and Brussels sought to maintain an institutional status quo.

The negotiators stressed however, many hurdles still needed to be cleared until a new government take office.

"Every party can still endanger everything," said Wouter Beke, the head of the Dutch-speaking Christian Democrats.

Even so, the solution for the electoral district in and around the capital was a huge step.

A linguistic border slices Belgium in northern, Dutch-speaking Flanders, southern francophone Wallonia and central bilingual Brussels, one electoral district around the capital always straddled that border, allowing francophone Brussels politicians to run in a sliver of Flanders. Dutch-speaking parties always argued this undermined their authority in the area.

Under the agreement, the district will be largely split along linguistic lines.