By Pavel Polityuk and Andrea Shalal

KIEV (Reuters) - The German and French foreign ministers said on Wednesday an attempt to revive a ceasefire in eastern Ukraine from midnight could set the scene for agreement next week on further peace moves.

Visiting Kiev with his French counterpart, Frank-Walter Steinmeier said Ukraine had agreed to abide by a new seven-day truce proposed by Russian-backed separatists and explicitly backed by Moscow.

French Foreign Minister Jean-Marc Ayrault said he also expected both sides to sign an agreement next week to withdraw their troops from the lines of conflict in three hotspots.

"In the next week we see an opportunity for a new dynamic in the conflict," Ayrault told reporters.

The agreement is expected at a regular meeting on Tuesday of the Organisation for Security and Cooperation in Europe (OSCE) with both sides in the conflict. It would be monitored and verified by OSCE observers.

A ceasefire was launched to coincide with the start of the school year on Sept. 1. It failed to stop all fighting.

"We are again at a crossroads," Steinmeier told a briefing. "We see a small sliver of hope in the back-to-school ceasefire ... but it is not enough."

If the ceasefire holds and the agreement is signed as expected, the foreign ministers of France, Germany, Ukraine and Russia could meet in New York next week on the sidelines of a meeting of the United Nations General Assembly.

That could prepare the way for a meeting of the leaders of the four "Normandy format" countries for the first time since October 2015.

MINSK DEAL STALLED

"The presence of Jean-Marc and Frank-Walter here in Kiev is evidence that the Normandy format works, that we must together force Russia to implement the Minsk agreements," Ukrainian Foreign Minister Pavlo Klimkin said at the briefing.

France and Germany helped broker the 18-month-old Minsk peace deal. Many of its key points, such as holding regional elections and returning control of Ukraine's border with Russia to Kiev, have long been stalled.

"We understand that to implement the Minsk agreements, to force Russia to implement them, we need a clear idea of the sequence of steps and guarantees of their implementation from Russia," he said.

Moscow denies accusations by Ukraine and NATO that it helps the separatists with troops and arms in a rebellion in which over 9,500 people have been killed since spring 2014.

Ayrault and Steinmeier emphasized their support for Ukraine and their rejection of Russia's annexation of the Crimea region of Ukraine in 2014. Steinmeier said that as the OSCE did not recognize the annexation, it would not send observers to Russian parliamentary elections planned in Crimea on Sept. 18.

Making his own separate trip to Kiev, British Foreign Secretary Boris Johnson said on Wednesday it was crucial for the West to maintain sanctions against Russia.

"Clearly it's up to the Russians primarily to make progress on the security side. But it's up to all sides I think in this conversation to make progress together," he said at a briefing.

(Writing by Matthias Williams and Alessandra Prentice; Editing by Andrew Roche)