A spokeswoman at the office says most the messages were posted on Dec.31, the day Rousseff was inaugurated.

She says the origin and content of the threats are being analyzed to determine if a full investigation is warranted.

She declined to be identified in line with internal regulations.

She said on Tuesday that did not know how many messages calling for Rousseff’s death had been sent.

One of the phrases posted on Twitter in portuguese read: “Now is the time to shoot Dilma, the same way they shot JFK.”

Another said a sniper should shoot her and her vice-president in the head.