The European Union announced Monday it had added 15 people to the list of Russian and Ukrainian figures hit with sanctions for their role in the Ukraine crisis.

"15 additional persons responsible for actions which undermine or threaten the territorial integrity, sovereignty and independence will be targeted with a travel ban and freeze of their assets within the EU," a statement said.

The names will be published in the EU's official journal on Tuesday, bringing to 48 the number of people listed for this category and hit with the same measures, it added.

Another 22, all Ukrainians, have had their assets frozen for fraud and embezzlement under now-ousted pro-Russian president Viktor Yanukovych.

The decision was taken at a meeting of the 28 member states' ambassadors to the EU to consider the bloc's next step on the crisis as Russia shows no sign of 'de-escalating.'

The measures fall short of the full-scale economic sanctions pressed by Washington which announced separately Monday it was taking action against another seven Russian officials and 17 firms linked to President Vladimir Putin's inner circle.

This was to punish "provocative acts" in Ukraine, where pro-Kremlin gunmen continue to seize government buildings, the White House said, adding that it was also tightening up licensing requirements for certain hi-tech exports to Russia that could have a military use.

The EU has balked at moving to a "Phase 3" of tougher sanctions given the extensive economic ties between many member states and Russia, but leaders have agreed to preparatory work on them.

"If there is additional escalation then there is the possibility to pass to Phase 3.... Currently, there is no de-escalation so we think additional (Phase 2 measures) are appropriate," the European Commission said earlier Monday.