BRUSSELS, Belgium — Ukraine successfully opened its second of six so-called enlargement clusters in Brussels on July 14, the next step on its path to becoming a full member country of the European Union.The six enlargement clusters are lists of reforms that Kyiv must carry out in order to become fully legally and politically aligned with the bloc. Ukraine opened Cluster 1 — which addresses the rule of law and democracy — on June 15.On the morning of July 14, Kyiv opened another cluster, with Moldova set to do the same later in the day. The EU's enlargement commissioner, Marta Kos, told journalists that the cluster covers external relations, defense, and the tackling of hybrid threats — topics grouped under Cluster 6."Both countries will contribute to the European security structure," Kos said, just ahead of the cluster opening ceremony.The remaining four clusters to be opened cover broad swathes of economic policy, the environment, agriculture, and transport, areas in which it may be harder for Kyiv to advance, as some EU countries fear Ukrainian competition.Ukraine's Deputy Prime Minister for European and Euro-Atlantic Integration Taras Kachka told journalists that "the process of Ukraine's accession is going without any interruptions" and that "we see no major obstacles for the process of accession."It is still unclear when exactly the remaining four clusters will open. Kos said in response to a question from the Kyiv Independent that "as you know, the European Commission has the opinion that everything is ready for all clusters to be opened. As soon as possible."However, Kos was clear that it depends "on the (Irish EU Council) presidency and again on the member states how quickly we could open the rest of the four clusters."In addition to Ukraine and Moldova opening the external relations cluster, Montenegro and Albania are each expected to close individual chapters, meaning that the EU has certified that the countries are aligned with the bloc on specific policy areas."Even if we would have to wait a bit, the technical work is going on," Kos reassured journalists."I hope that with the new government in Ukraine, we will get a new push for even more delivery from Kyiv," she added.