BERLIN, May 28 (Xinhua) -- Ukrainian Prime Minister Arseny Yatsenyuk said on Wednesday that his country should become a European country under the newly elected President Petro Poroshenko. Visiting Yatsenyuk was invited to a dinner by German Chancellor Angela Merkel at her Chancellery in Berlin, according to a statement posted on the website of the German government. Merkel told Yatsenyuk she was glad that the presidential election was held in Ukraine, and a result was already achieved in the first round of the ballot. Yatsenyuk said the security situation in Ukraine was still complicated, saying all countries, in particular Russia, should fulfill their international obligations. The goal, he stressed, is that Ukraine would become a European country with its new president. Preliminary official results showed that Poroshenko, a 48-year- old billionaire and independent politician, led Sunday's presidential election in Ukraine with a vote share of 53.7 percent.