TIMELINE - Previous U.S.-Russia spy incidents

(Reuters) - The Russian Foreign Ministry said on Tuesday U.S. spying allegations were baseless and it was regrettable that they followed Washington’s call for a “reset” in ties between the former Cold War adversaries.

The United States said on Monday it had arrested 10 alleged Russian spies days after President Dmitry Medvedev met Barack Obama in Washington.

Here is a timeline of previous U.S.-Russian spy scandals:

* SPYING FOR RUSSIA:

-- In February 1994, the United States arrested Aldrich Ames, a CIA counter-intelligence official. Ames pleaded guilty to spying for Moscow and is sentenced to life in prison.

-- In April 1996, Platon Obukhov, a Russian Foreign Ministry official, was arrested and charged with selling classified documents to Britain’s MI6 intelligence service. He was convicted in 2000.

-- In November 1996 the FBI arrested veteran CIA officer Harold Nicholson on charges of spying for Russia. He received a 23-year jail sentence.

-- In December 1996 the FBI arrested one its own agents, Earl Pitts, for allegedly selling national security secrets to Russia for more than $224,000 since 1987. He was later sentenced to 27 years in jail.

-- In October 1998, retired U.S. army intelligence analyst David Boone was arrested at a Washington hotel and charged with selling secrets to Moscow after an FBI sting operation.

-- In November 1999, U.S. military officials charged U.S. Navy code breaker Daniel King with selling data to Moscow.

-- In June 2000, the United States arrested retired U.S. Army Reserve Colonel George Trofimoff on charges of selling military secrets to the Soviet Union during the Cold War. He was later sentenced to life in prison.

-- In February 2001, FBI agent Robert Hanssen was arrested on charges of selling secrets to Moscow over 15 years. He was sentenced to life in prison in May 2002.

-- In June 2010, U.S. authorities charged 11 individuals with carrying out deep-cover work in the United States to recruit political sources and gather information for the Russian government.

* DIPLOMATIC INCIDENTS:

-- In 1971 Britain threw out 105 Soviet nationals accused of spying, one of the largest mass expulsions of the Cold War.

-- In 1983, France’s Socialist-led government expelled 47 Soviet diplomatic staff for alleged spying.

-- In October 1985, after the defection of senior KGB officer Oleg Gordievsky, Britain expelled 25 Soviet diplomats as alleged spies, triggering a chain of tit-for-tat expulsions. The Soviet Union threw out an identical number. The two sides expelled six more people each before calling a halt to the actions.

-- In 1991-92, Norway expelled nine Russian diplomats, the Netherlands and Belgium each ejected four and Denmark tossed out one after a series of spying allegations .

-- In May 1996, Britain ordered the expulsion of four Russian diplomats from their London embassy after Moscow ordered out nine British diplomats it said had been running a spy ring -- one of the most serious spy rows of the post-Cold War era. Britain said it retaliated for unjustified Russian allegations.

-- Following the 2001 Hanssen case, Washington expelled four Russian diplomats and ordered 46 to leave by July 1 of that year, saying it wanted Moscow to cut down its espionage activities. Russia expelled four U.S. diplomats and said another 46 must leave by the summer.

-- In 2007 senior British officials stated that Russian spying in London was now “at Cold War levels” and reportedly involved half of the accredited Russian embassy staff. British counter-intelligence said that they had seen “no decrease” in Russian agents in Britain since the end of the Cold War and that battling their efforts was distracting the agency from the menace posed by Al-Qaeda.

-- In June 2009, Germany’s counter-intelligence chief accused Russian intelligence of targeting the German energy sector to try and gain commercial advantage, warning of “intensified efforts.”

-- Analysts suspect Russian operatives have been seconded as part of the workforce for major state-led corporations abroad such as the energy giants Gazprom and Rosneft and are increasingly engaged in economic, technological and industrial espionage.