The Wednesday decision overturns a 2014 ruling by the EU's second-highest court to remove Hamas from the blacklist.

The EU first labeled Hamas a terror group in 2001, with the bloc freezing the faction's assets and imposing travel bans on its members. The Palestinian movement took power in Gaza in 2007 and has been in control ever since.

Three years ago, the EU's General Court ruled that the European bloc did not have enough evidence to keep Hamas on the blacklist. According to the judges, the policy was based on "factual imputations derived from the press and the internet" rather than acts examined and confirmed by authorities. The US and Israel slammed the move.

The EU governments appealed this ruling to the European Court of Justice in Luxembourg, which is the highest judiciary authority in the 28-member union.

After considering the 2014 decision, Luxemburg-based judges ruled that the General Court "should not have annulled" Hamas's status as a terror group. According to the ECJ, a competent authority is needed to place an organization on the blacklist, but there is no such condition for subsequent retention. The announcement came as a surprise as it goes before a previously expressed opinion by the court's senior lawyers.

The ECJ referred the case back to the General Court after announcing the ruling on Wednesday.

On the same day, the Luxembourg-based court ruled that Sri Lanka's separatist Liberation Tigers of Tamil Eelam (LTTE) should be taken off the EU's terror list.

dj/ng (dpa, Reuters, AFP)