LAS PALMAS, Spain, (Reuters)

Passengers overpowered a suspected armed hijacker who had commandeered a Mauritanian plane yesterday, when he was knocked off his feet during a hard landing, a source close to the Mauritanian presidency said.

The Air Mauritania Boeing 737 was on an internal flight in Mauritania when the hijacker, armed with pistols, demanded to be flown to France, officials said.

The pilot landed in Spain's Canary Islands instead, where Spanish police arrested the man.

"When the pilot landed, he deliberately braked very hard. The man fell to the ground and was jumped on by passengers. He fired two bullets but there are no serious injuries," said the Mauritanian source.

A spokeswoman for the Spanish emergency services said 20 people suffered minor cuts and bruises but added she knew of nobody being injured by gunfire, as one emergency services source had reported.

Spain's Interior Ministry said security forces arrested the hijacker and freed all 71 passengers and eight crew after the plane touched down at Gando airport on the island of Gran Canaria.

Media reported the hijacker was North African.

Air Mauritania's Director General Mohamed Ould El Moctar said the crew told him nobody was hurt and that the hijacker had acted alone.

Train bombings

"The lone hijacker was armed with two pistols but it is not clear whether these were real or not," he told Al Jazeera television.

The hijacking came on the same day that Spain began the trial of 29 people, mostly Moroccans, for the 2004 Madrid train bombings which killed 191 people, and days after al Qaeda called for attacks on Mauritania's rulers.

In an audio message quoted by Arab media this week, al Qaeda's second-in-command Ayman al-Zawahri said Muslims should attack Mauritania's leaders for recognising Israel.

"I call especially on our people in Mauritania ... to take a sincere Jihadi stand against treacherous rulers who recognised Israel and betrayed the Islamic nation," Zawahri said.