The Aksa Martyrs Brigades announced on Sunday that its members have succeeded in manufacturing chemical and biological weapons.
In a leaflet distributed in the Gaza Strip, the group, which belongs to Palestinian Authority President Mahmoud Abbas's Fatah Party, said the weapons were the result of a three-year effort.
According to the statement, the first of its kind, the group has managed to manufacture and develop at least 20 different types of biological and chemical weapons.
The group said its members would not hesitate to add the new weapons to Kassam rockets that are being fired at Israeli communities almost every day. It also threatened to use the weapons against IDF soldiers if Israel carried out its threats to invade the Gaza Strip.
"We want to tell [Prime Minister Ehud] Olmert and [Defense Minister Amir] Peretz that your threats don't frighten us," the leaflet said.
"We will surprise you with our new weapons the moment the first soldier sets foot in the Gaza Strip."