The Romanian, Greek and Bulgarian prime ministers signed on Monday in Varna a joint declaration whereby they emphasize the need to strengthen the use of the EU - Ukraine solidarity lanes, including through a possible increase in the capacity of the ports of Constanta and Sulina, and the potential of transport on the Danube, by ensuring all-year-long navigability."We are gravely concerned by Russia's military build-up and aggressive posture in the Black Sea and call for an immediate end to unlawful restrictions to freedom of navigation, which further jeopardize global food security. In this context, we stress the need to further consolidate the use of EU - Ukraine Solidarity Lanes by pursuing the possible increase in the capacity of the Constanta and Sulina Harbors, the potential of the transport on the Danube by ensuring the navigability all year long, as well as by exploring the involvement of the Bulgarian ports of Varna and Bourgas and the Greek ports of Thessaloniki and Alexandroupolis," the joint Declaration signed on the occasion of the Romania - Bulgaria - Greece trilateral meeting reads.Also, the signatories undertake to build cross-border intermodal infrastructure along the Danube River, including new bridges at Giurgiu - Ruse and other locations, in accordance with European standards for military mobility and sustainability."We condemn the continuing Russian shelling against civilian targets and infrastructure in Ukraine, including the Ukrainian ports on Danube River. Bulgaria and Greece express strong concern over the recent drone debris found on the territory of Romania and reiterate their unwavering support to Romania as a NATO Ally and EU Member," the document notes.The parties express support for a continuous NATO focus and strong NATO presence in the Black Sea, which are seen as key for ensuring deterrence and prevention of conflicts in the Southeastern flank of the Alliance."We also stress that military drills at sea should take place in accordance with international law. In this context, we express full solidarity with Bulgaria in the face of the Russian warning area for military drills declared within large part of the Bulgaria's Exclusive Economic Zone. We agree to further cooperate in enhancing the Alliance's capacity to ensure adequate and sustainable fuel supply to NATO's Eastern Flank," the declaration goes on to read.Also, the three signatory states reaffirm their determination to support the European membership perspective of the Western Balkans, as well as that of Ukraine, the Republic of Moldova and Georgia, based on the fulfillment of the EU accession criteria and candidates' "own merits" in achieving the necessary reforms.Romania, Bulgaria and Greece reconfirm their resolute support for Ukraine's independence, sovereignty, territorial integrity and inviolability, and pledge to continue to cooperate in order to ensure appropriate multidimensional support for the Republic of Moldova, considering the security challenges it faces."Faced with increasing levels of hybrid attacks and disinformation, spread by state and non-state actors in the region, we are committed to enhance our coordinated efforts in countering foreign malign influence and strengthening strategic communication, ensuring synergies and complementarity," the declaration states.