A terrorist bomb remains a possible cause for the disappearance over the Atlantic Ocean of an Air France jetliner carrying 228 people, dpa cited French Defence Minister Herve Morin as saying today in Paris. "We have no right to exclude terrorism," Morin told journalists in the French capital. "But we have no element or trail that would permit us to corroborate that." The French defence minister noted that he had not heard of any threats to the flight or of any group or individual claiming responsibility for bringing the aircraft down. "But in most cases of terrorist acts against airplanes, there were no claims of responsibility," Morin said. Morin said that Paris was sending a nuclear-powered submarine to the search area, some 1,200 kilometers off the coast of Brazil, because it is equipped with extremely sensitive sonar detectors. "(It) can help find the black boxes," Morin said. The mystery surrounding the fate of the Airbus A330-200, which vanished early Monday on a flight from Rio de Janeiro to Paris, deepened after Brazilian officials admitted that no trace of the plane or its 228 occupants had been found. At the same time, the French Office of Accident Investigations and Analyses (BEA), which is leading the investigation into the disaster, issued a statement warning against "any hasty interpretation or speculation on the basis of partial or unconfirmed information." At the current stage of the inquiry, investigators have only established two facts about the crash, the BEA said. One was "the presence near the airplane's planned route over the Atlantic of significant convective cells typical of the equatorial regions," suggesting stormy weather at the time of the crash. In addition, "based on the analysis of the automatic messages broadcast by the plane, there are inconsistencies between the various speeds measured," the BEA said. Late Thursday local time, a Brazilian military spokesman said in Recife that pieces of wreckage fished out of the sea did not come from the plane. "We have so far recovered no piece of the crashed airplane," air force spokesman Ramon Cardoso said. A wooden palette plucked from the waters by a helicopter was "100 per cent" not from the Airbus A330-200 that disappeared while on flight from Rio de Janeiro to Paris, he said. A kerosene slick spotted in the sea also did not stem from the aircraft, but was in fact oil from a ship. "The search goes on," Cardoso said. French Junior Transport Minister Dominique Bussereau on Friday urged "extreme caution" in regard to the fragments fished out of the waters. "I remind you that our airplanes and our ships have seen (no wreckage). It is our Brazilian friends who have seen things which they...said came from the plane," Bussereau told RTL radio. Brazilian searcher planes had reported sighting pieces of wreckage in the sea, including what they said what a seat, which prompted Brazilian authorities to declare that there was "no doubt" the debris came from the missing aircraft. Air France said Friday that, because of the accident, it will redesignate its route from Rio de Janeiro to Paris. Formerly designated as flight AF 447, the route will be known as AF 445 starting on Sunday, an Air France spokesman told the German Press Agency dpa. French Foreign Minister Bernard Kouchner will be among the last passengers to take flight AF 447. "If you permit me, I will fly this evening with an Airbus 330 on flight 447 back to Paris," Kouchner said late Thursday local time in Rio de Janeiro, where he had taken part in a memorial for the crash victims. The aircraft was carrying 216 passengers from 32 countries and a crew of 12 when it vanished mysteriously.