Russian Foreign Intelligence Service (SVR) made no comments Tuesday on reports from the United States over the arrest of some Russian spies, while the Foreign Ministry said it was currently investigating these reports.

This drawing dated June 28, 2010 shows five of the 10 arrested Russian spy suspects in a New York courtroom. The United States cracked wide open Monday an alleged Russian spy ring, announcing the arrest of 10 "deep-cover" suspects after unraveling a mission secretly monitored by the FBI for more than a decade.[Xinhua]

"The information we do not comment," said Sergei Ivanov, head of the SVR press bureau as quoted by news agencies.

Russian Foreign Ministry said Tuesday that it was investigating the reports about alleged Russian spies detained in the United States, news agencies reported. The ministry meanwhile said the information it has received was contradictory.

"Messages are being studied, which are controversial and require further clarification," said an official from the Information Department of the Foreign Ministry.

The official also declined further comments on the incident.

U.S. Justice Department said Monday authorities have arrested 10 suspects on charges of spying for Russia. Court documents show they tried to penetrate decision-making circles of the U.S. government.

The suspects were all members of a Russian intelligence program that operates inside the United States, and they all were arrested on Sunday.

According to a Justice Department statement, they were allegedly carrying out long-term, "deep-cover" assignments in the United States on behalf of the Russian Federation. One suspect remains at large.

Russian President Dmitry Medvedev has just concluded his tour to the United States, during which he and his U.S. counterpart Barack Obama vowed to reset and broaden bilateral ties.