MOSCOW Russia foiled "major terrorist attacks" on World War Two victory celebrations last month in Moscow and newly annexed Crimea, the FSB security service said on Tuesday.
Details of the alleged plots could not be verified but the FSB's statements, suggesting patriotic Russian symbols were targeted, could be intended to fuel nationalist sentiment during the Ukraine crisis and rally support for President Vladimir Putin.
Itar-Tass news agency quoted the FSB as saying it was investigating a number of Russian citizens suspected of preparing an attack on May 9, the Victory Day holiday, using a home-made bomb packed with bolts, screws and nails.
The group were arrested two days before the planned attack, it said.
In a separate speech to the National Anti-Terrorism Committee, FSB chief Alexander Bortnikov said the alleged Crimean plot - which the security service first made public last month - had targeted the Eternal Flame war memorial and a monument to Soviet state founder Vladimir Lenin in the regional capital Simferopol. He said two home-made bombs were found.
The FSB, a successor to the Soviet-era KGB which Putin used to work for, said on May 30 it had arrested four men it said were members of a far-right Ukrainian nationalist group.
The group, Right Sector, said at the time it had never engaged in terrorism and called the allegation an FSB provocation. Supporters of the four men, who include a well known film maker, have protested their innocence.
Russia seized control of Crimea from Ukraine in March and relations between the two former Soviet republics remain very tense. Ukrainian authorities fighting pro-Russian separatists in the east of the country have also portrayed their offensive as a fight against terrorism.
Bortnikov said in his speech that Russia had so far foiled six attacks this year and "liquidated" 130 militants. He warned of an ongoing threat from groups with foreign support.
"Crime bosses and heads of various extremist groups, with the support of their foreign sponsors, are continuing to carry out plans to commit terrorist acts in the Russian Federation," he said.
Russian news agencies, in their reports of his speech, did not say whether he identified the alleged foreign backers.
Putin, in power since 2000, has frequently stressed his commitment to stamp out terrorism as part of a tough guy leadership style that plays well with Russian voters.
The main security threat for the past two decades has come from Islamist militants who routinely carry out shootings and bombings in the south of the country, punctuated by more ambitious attacks in the Russian heartland.
These have included a Moscow theater siege in 2002, in which about 130 hostages died, and several attacks on the capital's transport network. At the end of last year, at least 34 people were killed in two bombings in the southern city of Volgograd, weeks before Russia hosted the Winter Olympics.
(Editing by Alison Williams)