Ukrainian opposition leader Viktor Yushchenko will undergo new tests over the weekend in a Vienna hospital where he was admitted Friday to look into a mystery illness, the head of the hospital said.

"We will check the size and functioning of all his organs, including his intestines, re-examine his blood and look again for all possible causes of poisoning," Michael Zimpfer, director of the Rudolfinerhaus hospital, told reporters.

"We will also carry out biopsies, including of his skin," he said.

"He (Yushchenko) should leave the clinic the day after tomorrow(Sunday) and the results of these new tests should be known at the beginning of next week," he said.

Upon arrival at the hospital earlier on Friday, Yushchenko, who claims he was poisoned ahead of last month's elections, told reporters he was feeling better and expected to stay in Vienna for two days.

Yushchenko, 50, fell ill on Sept. 6 and four days later was admitted to the Rudolfinerhaus clinic, where he remained until Sept. 19.

Source: Xinhua