Ukrainian Prime Minister Yulia Tymoshenko was hospitalized on Thursday with an exacerbation of a disease, First Deputy Prime Minister Oleksandr Turchynov said, according to Itar-Tass.

She was hospitalized due to aggravated flu after gas supply negotiations in Moscow, official reports said.

Vice PM Oleksandr Turchynov said Tymoshenko`s health condition was "serious" and pointed out her flu aggravated as despite being ill she headed the recent Ukrainian delegation to Russia.

Tymoshenko,widely known as the gas princess of Ukraine, flew to Moscow on February 21 to reach long-term agreements with energy monopoly Gazprom and stabilize sensitive gas relations with the Russian Federation.

Ukrainian media reported Tymoshenko visited Moscow to show she is not satisfied with the deal struck and to declare her stalwart position that Ukrainian government officials must negotiate directly with Gazprom.

Tymoshenko was not present at the government’s meeting on Wednesday.

Reports of her ill-health come not for the first time.

Tymoshenko was absent from a meeting of the Ukrainian Security Council on Wednesday because of throat angina.

The agenda had on it the land issues.