“We launched an urgent inquiry into the men’s backgrounds as soon as they were pinpointed as having possible terrorist links. This deep and wide-ranging investigation has allowed us to clear them,” a ministry spokesperson said.

Posthumous security checks into the backgrounds of the men found that they only “shared the same name” as known Muslim radicals.

Despite the breakthrough, the fact that the men were not investigated before boarding the doomed flight on May 31 has exposed serious holes in airport security in Rio de Janeiro, The Sun reported on Thursday.

The possibility of a terror link in the crash of the Air France jet into the Atlantic had emerged on Wednesday night with a leading TV channel reporting that two of the passengers had shared names with some terror suspects.

The French have confirmed that the two men, in their 20s and of North African or West Asian origin, boarded flight 447 unhindered.

Meanwhile, Air France is not yet convinced that faulty speed sensors were to blame for the loss of one of its planes over the Atlantic, but it is replacing old sensors as a precaution, the airline’s chief executive said on Thursday.

Pierre-Henri Gourgeon told reporters that Air France was in a state of shock over the worst disaster in its 75 year history and expected more information about what happened within a week.

Air accident investigators have said the Airbus registered inconsistent speed readings just before contact was lost, raising speculation that the pilots might inadvertently have flown at the wrong speed and precipitated the disaster.

Air France subsequently reported that it had noticed temporary loss of air speed data on previous Airbus flights due to ice collecting in the sensors, known as pitot tubes, and said it was speeding up a pre-planned replacement programme.

“As circumstances would have it, the first replacements arrived practically on the eve of the accident, on the Friday,” Gourgeon told a news briefing, adding, “I am not convinced that speed sensors were the cause of crash.”

Gourgeon said the planemaker had reassured clients that all three types of speed sensors available for its jets were safe, including the one used on the downed A330.

Industry sources said the planemaker had also ruled out for the time being that there was an electrical power failure or loss of cockpit instrument display on the Air France jet.