Germany and France have been brokering peace talks between Russia and Ukraine for the past six years in an effort to end a simmering conflict in eastern Ukraine, near the Russian border.

Maas said that a new ceasefire that came into effect last month has renewed hopes for the peace effort. After a meeting with his Ukrainian counterpart Dmytro Kuleba, Maas spoke of “substantial progress.”

In addition to the ceasefire, this also applies to the exchange of prisoners, clearing mines and establishing transition points between the areas of the conflicting parties, according to Maas.

There have been more than 20 attempted ceasefires since the conflict erupted in early 2014 following Kiev’s ouster of the country’s pro-Russian president amid a political pivot away from Russia and towards the European Union.

The Organization for Security and Cooperation in Europe (OSCE) recorded more than 100 violations within days of the latest ceasefire attempt starting in late July.

Despite the violations, Maas described the ceasefire as a “hopeful sign,” in comments ahead of his trip to Kiev.

“This ceasefire, which has lasted for over four weeks, is the longest since 2014 and that is a hopeful sign. We want to build on that,” Maas said.

“We want to move forward faster in the Minsk process – that’s why I’m travelling to Kiev,” Maas said in a statement released by the Foreign Ministry shortly before his departure on Monday morning.

Maas was also to meet Ukrainian President Volodymyr Zelensky and Prime Minister Denys Shmyhal on his visit.

Along with France, Germany oversaw the most recent talks between Russia and Ukraine in December, ahead of the fifth anniversary of the 2015 signing of the Minsk peace agreement.

Ukraine’s new leadership, in power since last year, dismisses the agreement’s demand to grant more autonomy to the eastern Donetsk and Luhansk regions, claiming the previous government agreed to this under duress.

Kuleba emphasized on Monday that Ukraine was not prepared to make concessions in an effort to end the conflict.

“Ukraine will never make concessions on questions of territorial integrity and the development towards a European and democratic country,” Kuleba said.

Russia, which represents the rebels at international peace talks, denies allegations of direct involvement in the conflict. About 13,000 people have died in the fighting, the United Nations estimates.