TUNIS, Jan. 28 (Xinhua) -- The Tunisian Presidency on Thursday confirmed that the head of the presidential cabinet was sick after opening a suspicious envelope addressed to Tunisian President Kais Saied.

The envelope, without the name of its sender, was received and opened on Monday by the director of the presidential cabinet, Nadia Akacha, the presidency said in a statement.

"Upon opening the envelope, which was empty, she suffered from discomfort including a dizziness, headache and difficulty seeing and she was taken to hospital in Tunis," it said.

An agent who accompanied Akacha also suffered from the same symptoms, but less severe, it noted.

The presidency said the envelope was placed in a paper shredder before it was decided to submit it to the specialized services of the Ministry of the Interior.

"It was not possible, so far, to determine the nature of the substance that was inside the suspected poisoned envelope," it added.