Brussels (AFP) - NATO head Jens Stoltenberg told AFP Thursday there was still a "strong" Russian presence in eastern Ukraine in support of pro-Moscow rebels although a recent ceasefire seems to be holding.
Stoltenberg said he backed the continuation of European Union and United States sanctions against Russia over its involvement in Ukraine until Moscow changes its behaviour.
"There is no doubt that there is a strong Russian presence in the eastern part of Ukraine," Stoltenberg said in an interview at NATO HQ in Brussels.
"There (are) Russian forces there, there (is) Russian equipment and Russia continues to train and to assist the separatists."
Stoltenberg said it was an "encouraging" sign for the implementation of the Minsk peace agreement, which was brokered by France and Germany in February, that a ceasefire in eastern Ukraine has held.
"All the parties of the agreement have still a long way to go before we can say that the agreement is fully implemented, but at least it is an encouraging sign that for the first time since this agreement was first signed last fall, the ceasefire seems to be holding," he said.
"When there is no violence going on, no fighting going on it is easier to make progress also on the other elements of the agreement," which include the withdrawal of heavy weapons and restoration of full Ukrainian control of the border with Russia.
"Russia has to change behaviour if they (are going) to do something with the economic sanctions," he said. "Therefore I think sanctions should continue."
Damaging EU economic sanctions against Russia come up for review in December, with EU leaders saying a decision on whether they will be lifted depends on Moscow fully implementing its Minsk commitments to cut support for the rebels and restore the border.