Lithuania must block a deal between the European Union and Cuba because island's the communist rulers are using it to legitimise repression, US Secretary of State Mike Pompeo said on Friday. Staunch US ally Lithuania is the only EU state yet to approve the deal -- the government said it was prepared to ratify but the right-wing opposition is strongly opposed. The EU and Cuba signed the Political Dialogue and Cooperation Agreement (PDCA) in 2016 but it will not be fully applied until it is ratified by all EU members. "We are grateful to Lithuania for not ratifying the agreement and ask that you continue to vote against it, as a symbol of your support for the Cuban people," Pompeo told Lithuanian Prime Minister Saulius Skvernelis in a letter seen by AFP. Pompeo insisted Cuba's government was using the PDCA "to validate its dictatorial, repressive actions" and that the "political situation and human rights conditions in Cuba have dramatically worsened" in recent years. A spokesman for Lithuania's prime minister confirmed the receipt of the letter but declined further comment. In contrast to the hardline stance of the administration of US President Donald Trump, the EU has been seeking to normalise relations with Cuba. Pompeo's request came a month after the Lithuanian parliament's foreign affairs committee approved ratification. After earlier insisting Lithuania did not want to "become the only brakes" on ratification, Foreign Minister Linas Linkevicius said on Friday that he "hopes to find an optimal solution". Referring to the US as a "strategic partner", Linkevicius said Lithuania wanted to avoid "choosing between the interests of EU and those of US". Lithuania's right-wing opposition, which has repeatedly invited Cuban dissidents to the parliament, remains strongly opposed. Conservative party leader Gabrielius Landsbergis told AFP the agreement would only "benefit the dictatorship". By holding off the deal, Lithuania is "demonstrating solidarity with our strategic partners in the US Congress", he added. vab/mas/jxb