President Hu Jintao will pay state visits to Kazakhstan, Russia and Ukraine during the period from 12 to 20 June, a spokesman for the Chinese Foreign Ministry said today.     The spokesman added that during the tour the Chinese president will attend the Shanghai Cooperation Organization (SCO) annual summit in the Kazakh capital of Astana and the 15th session 15 of the International Economic Forum in St. Petersburg, Russia.       The Astana summit marks the tenth anniversary of the founding of the Shanghai Cooperation Organization which was established in 2001. It comprises China, Russia, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan.