LONDON (CNNMoney) — European finance ministers concluded a marathon meeting Wednesday without finalizing the details of a debt-reduction package for Greece.

The absence of an agreement endangers the release of the next round of Greece’s international bailout package, funding the country needs to remove the threat of bankruptcy and a messy exit from the eurozone.

The source of the delay Wednesday was not immediately clear, but negotiations lasted nearly 12 hours. The group has agreed to meet again on Monday to continue talks.

Jean-Claude Juncker, the Eurogroup president, said in a statement that the discussion was “extensive” and that progress was made.

“The Eurogroup … made progress in identifying a consistent package of credible initiatives aimed at making a further substantial contribution to the sustainability of Greek government debt,” Juncker said.

Bailout payments to Greece were suspended in June after Athens fell behind schedule in cutting its budget deficit and implementing economic reforms. Greece will need additional funds of some 30 billion euros to tide it over until 2016. Read further.