Russian police are taking a complex of measures aimed at ensuring security in public transportation systems over the threat of possible terrorist attacks, a high-ranking interior ministry official said on Wednesday.

The official, whose name was not given, confirmed information released by authorities on Tuesday suggesting high probability of terror attacks that may be staged on ground transport vehicles and in the underground metro.

"This information has been obtained from foreign partners and is sufficiently grounded," the official was quoted by the Itar-Tass news agency as saying.

Russian police are calling on citizens to be vigilant and cautious in the current circumstances.

"We ask Russian citizens to give special attention to suspicious neglected things left in public places, near bus stops and in the metro, as well as to report to police about persons behaving inadequately, for instance, that are very nervous," the official said.

Moscow police have also enhanced security in the city metro, said Viktor Biryukov, head of the information and public relations department of the city's main police department.

"Security of passengers will be ensured by additional squads of police officers in the metro. The number of policemen on stations, junctions, as well as at entrances to and exits from the underground railway will be increased," Biryukov said.

Additional groups of policemen with sniff dogs for searching and discovering explosive substances and devices have also been sent to the Moscow underground railway, he said.

Source: Xinhua