The European Space Agency says its Mars Express orbiter has sent back its first high-resolution pictures of the planet's surface, showing a canyon that may have been shaped by ancient water flow.

Agency officials say they have received a spectacular image of the Valles Marineris, the Grand Canyon of Mars, taken from nearly 300 kilometers above the planet's surface.

The officials said the photos show a landscape apparently shaped mostly by water erosion, with surface features made up of mountain ranges, valleys and small plateaus. A number of scientists have theorized that Mars once held water, a key ingredient for known forms of life.

The Mars Express, the first European craft to reach Mars, is equipped with a number of sophisticated instruments to examine the planet. These include a powerful radar capable of searching beneath the planet surface for signs of water and ice.

The spacecraft reached Mars in late December, just two weeks before NASA landed the American rover Spirit on the Martian surface. The Mars Express launched its own landing craft carrying the Beagle II rover towards the surface after its arrival. But the vehicle has not been heard from since it was due to land on the Red Planet December 25.