Turchnivov said today that investigators were examining a number of actions of Volodymyr Satsyuk.
Satsyuk and his former boss, Ihor Smeshko, have been accused of complicity in September's near-fatal poisoning of Yushchenko, who was a candidate at the time opposing the handpicked candidate to succeed longtime President Leonid Kuchma.
Yushchenko fell ill after a dinner with the two top security officials.
Yushchenko was elected president amid massive protests that have been deemed an Orange Revolution
, after the color identified with opposition backers.
Turchinov said only that he will discuss what he called "more serious issues" later.
Also today, Ukraine's opposition Communist Party proposed a bill in parliament to re-nationalize major companies in the mining and metallurgical sectors in order to increase the state's role in strategic sectors of the economy.
In Moscow, new Ukrainian Defense Minister Anatoliy Hrytsenko said that Russia may keep its lease for its Black Sea fleet at the Ukrainian port of Sevastopol until 2017, when it is due to run out.
Hrytsenko said he believes that the presence of the Russian fleet will not hinder Ukraine's bid to join the NATO military alliance.
NATO said today that it has established a trust fund to help Ukraine destroy 133,000 tons of surplus munitions, 1.5 million small arms and light weapons, and portable air-defense systems.
(compiled from wire reports)