WASHINGTON, May 25 (UPI) -- Unable to choke off fuel shipments for the war machine of Yugoslav President Slobodan Milosevic, the United States and its 18 NATO allies plan to crank up the pressure on Ukraine to enforce the embargo and on Cyprus to freeze the accounts Belgrade uses to pay for the oil. Following a meeting today with German Foreign Minister Joschka Fischer, Secretary of State Madeleine Albright said that the voluntary embargo had been successful in stopping fuel shipments in the Adriatic Sea. But NATO is still concerned about oil reaching Belgrade on barges in the Danube River, an issue Albright said she would soon take up with Ukraine. Furthermore, Albright said she had dispatched a team of American experts in sanctions enforcement to the Balkans to study ``how we can contain it.'' ``By and large the oil that is coming in by sea has been substantially cut down,'' Albright said during a joint news conference with Fischer. ``But we are concerned by the traffic up and down the Danube...I will be talking to the Ukrainians about the allegations.'' Depriving Milosevic of fuel for his tanks, aircraft and armored personnel carriers has been a major goal of NATO's air campaign against the Federal Republic of Yugoslavia, with alliance pilots striking time and again at refineries and associated infrastructure. President Clinton and his counterparts spoke eloquently during a summit in Washington last month about the hypocrisy and contradiction of risking pilots' lives on such missions while not enforcing a fuel embargo. But the principled rhetoric at the summit failed to convince all 19 alliance members of the need for a mandatory embargo backed-up with military force for fear it might lead to hostilities with Russia, Belgrade's traditional source of fuel, or require a formal declaration of war. The alliance opted instead for a voluntary embargo, which has apparently been effective in stopping tanker traffic through the Adriatic Sea. But NATO officials, speaking on conditions of anonymity, say Ukrainian barge captains continue to bring shipments of Russian oil up the Danube River to Yugoslavia. Although the governments of Ukraine, Bulgaria and Romania are not directly involved in providing oil to Belgrade, alliance officials say they could do more to cooperate with the embargo. During a meeting in Brussels last week, they say NATO made a ``firm'' request to Ukrainian Foreign Minister Boris Tarasyuk for more cooperation with the embargo. Tarasyuk responded sharply that the war was doing major collateral economic damage to cash-strapped Ukraine, costing his nation $220 million in trade opportunities the past two months. The officials say Romania and Bulgaria, both of which want to be included in the next round of NATO expansion, argue that the Danube Convention of 1948 forbids interference with traffic on the international waterway. Despite the treaty, a Soviet-era pact that alliance officials argue is no longer in effect, Romania and Bulgaria have been more cooperative with the embargo than they were during the war in Bosnia-Herzegovina five years ago. In addition to requesting more cooperation from the Danube riparian states, NATO officials say they are pressuring Cyprus to join Europe in freezing bank accounts Milosevic draws from to pay for fuel and other war materiel. They say Cyprus, which maintains strict banking secrecy laws, has become a haven for money launderers and other international criminals. Cypriot officials, speaking on conditions of anonymity, say there is no basis for freezing Yugoslav accounts since the U.N. Security Council has not imposed any new sanctions on Belgrade. But the officials, in Washington and in Nicosia, say they plan to cooperate more in hopes it will enhance their prospects for joining the European Union. ---- Copyright 1999 by United Press International All rights reserved ----  