Controversy continue to surround the doomed Phobos-Grunt probe that plunged to Earth over the weekend as Russian investigators said they will conduct tests to check if U.S. radar emissions could have interfered with the doomed spacecraft.

Experts, however, have dismissed such claims.

Russia's space agency Roscosmos have earlier raised the possibility that their satellite mission could have been sabotaged, insinuating that the United States was probably involved.

"We don't want to accuse anybody, but there are very powerful devices that can influence spacecraft now. The possibility they were used cannot be ruled out," Roscosmos head Vladimir Popovkin was quoted as saying.

Russia's state news agency RIA Novosti has reported that Yury Koptev, a former head of Roscosmos, said that investigators will conduct tests to check if U.S. radar emissions could have affected the Phobos-Ground space probe.

"The results of the experiment will allow us to prove or dismiss the possibility of the radar's impact," said Koptev, who is heading the government commission, charged with investigating causes of the probe's failure.

NASA spokesman Bob Jacobs said the U.S. space agency was not using the suspected military radar equipment at the time when the Russian spacecraft encountered problems. At that time NASA was using radar in the Mojave desert of California and in Puerto Rico, Jacobs said.

Konstantin Kakaes, a Bernhard L. Schwartz Fellow at the New America Foundation, said in an article that the U.S. did not shoot down Russia's Mars probe even if it could have.

"The claim that Phobos-Grunt was shot down is absurd. But that's not because it would be hard to do. It's easy, if you can launch satellites, to destroy them, and to do so with deniability isn't much harder. Had the United States wanted to destroy Phobos-Grunt, it could have," Kakaes said.

In another article at Time Science, writer Jeffrey Kluger said that space watchers in both the U.S. and Russia were rooting for this mission to succeed, and that the loss of Phobos-Grunt is equally big for space science as a whole.

"It's worth noting that the U.S. would have nothing to gain and a whole lot to lose by monkeying around with a Russian Mars probe - especially since we're now dependent on Roscosmos rockets to ferry us to the NASA-built International Space Station," Kluger said.

Other space experts, on the hand, said the possibility of U.S. interference should be considered only after investigating all other possible causes.