Mangalyaan: Nasa's Curiosity tweets greeting to India's Mars probe

India's Mangalyaan Mars probe has been welcomed into the planet's orbit by a friendly tweet from the US space agency Nasa's Curiosity Rover.

Curiosity, which has been on the Mars surface for two years, tweeted "Namaste @MarsOrbiter" and congratulated India on its first interplanetary mission.

@MarsOrbiter, in one of its first ever tweets, replied: "Howdy @MarsCuriosity? Keep in touch. I'll be around."

India is only the fourth nation or geo-bloc to have a probe at Mars.

Only the US, Russia and Europe have previously sent missions to Mars, and India has succeeded on its first attempt - an achievement that eluded even the Americans and the Soviets.

The latest US satellite, Maven, arrived at Mars on Monday.

The Mangalyaan - which means "Mars craft" in Hindi - will soon begin work studying the Red Planet's atmosphere.

It will take pictures of the planet, study its atmosphere and try to detect methane in the Martian air, which could be an indicator of biological activity at, or more likely just below, the surface.

Within the first fours hours of launching its Twitter account, @MarsOrbiter had more than 32,000 followers and #Mangalyaan, #IndiaAtMars, #marsorbitormission and #Martian were among the top 10 Twitter trends in India.

Mangalyaan - more formally referred to as Mars Orbiter Mission (MOM) - was launched from the Sriharikota spaceport on the coast of the Bay of Bengal on 5 November 2013.

Indian Prime Minister Narendra Modi said the country had achieved the "near impossible".