Moscow and Kyiv have agreed that the number of OSCE observers monitoring the fragile ceasefire in eastern Ukraine can be doubled to 1,000.
And teams from the European security watchdog should also get access to locations where heavy weapons are being stored.
The European Union’s foreign policy chief Federica Mogherini described the ceasefire as ‘not perfect’ but improving.
She said EU sanctions against Russia would remain and stressed member nations’ unity.
“We are united on any single action we do vis-à-vis Russia, vis-à-vis the situation in Ukraine,” she told reporters after a meeting of EU foreign ministers in the Latvian capital, Riga.
Mogherini said the EU could not ease sanctions now and French Foreign Minister Laurent Fabius stressed the situation would have to improve sharply before there would be pressure to loosen them.
At the same time, Fabius opposed any tightening at the moment.
“It would be paradoxical at the very time that Minsk is being applied to reinforce the sanctions now,” he said.
The EU has joined the United States in imposing sanctions on Russia but has found it increasingly difficult to agree on tougher measures as many member states rely heavily on Russia for energy.
The truce, agreed last month in Minsk, has eased pressure for new sanctions, but the EU must decide soon whether to extend current economic curbs on Russia that expire in July.
Lithuanian Foreign Minister Linas Linkevicius, an EU hawk on Russia, said extending sanctions to the end of the year was “the least we can do”.
“Everyone is for unity but you know unity to do nothing is not for me. I don’t like it. So we have to be united on doing something,” he told reporters.
Russia denies accusations by Ukraine and Western governments that it has been sending troops and weapons to support separatists.
While violence continues in eastern Ukraine despite the ceasefire, OSCE head Lamberto Zannier said the level of hostilities had fallen and some heavy arms had been removed.