As Europe remains on high alert following the Paris attacks, several countries have increased their threat level while others have received tip offs of potential acts of terrorism. London has also had a bomb scare.
British police carried out a controlled explosion close to Baker Street tube station on Thursday after a car was abandoned nearby.
Authorities later said, however, that the vehicle was not suspicious and no criminal investigation was underway. Baker Street station and nearby roads were reopened shortly afterwards.
Earlier that day two men were arrested in the northern English city of Manchester on suspicion of making a bomb threat, causing passengers to be evacuated from an easyJet flight.
Swedish authorities also arrested a man on Thursday suspected of planning a terrorist attack. The country's threat assessment level also remains at its highest ever, indicating a high probability that "persons have the intent and ability to carry out an attack."
Italy landmarks 'potential targets'
In Italy, police are on the hunt for five terror suspects, following a tip-off from the US about possible "Islamic State" (IS) attacks, in tourist hotspots such as Rome and Milan and the Vatican.
Italian Foreign Minister Paolo Gentiloni said on Thursday that the US embassy in Rome posted a security warning on its website identifying some of Italy's best-loved landmarks as "potential targets", including St Peter's Square, La Scala and the Duomo cathedral in Milan.
The warning said a terrorist group might use "similar methods used in the recent Paris attacks." The series of bombings and shootings in the French capital last Friday killed 129 people and left more than 350 injured.
"Since yesterday afternoon, our security forces have been working to find five people," Gentiloni told Rai 3 television. The names of the five suspects were provided by the US Federal Bureau of Investigation (FBI). The agency didn't supply details of any plots, however.
In light of last week's Paris attacks, Italy has deployed 700 extra troops in Rome, on top of 1,300 who were already involved a highly-visible "safe streets" operation.
IS targets destroyed
Meanwhile, the French military said it had destroyed 35 "Islamic State" targets in Syria since last week's Paris attacks.
Military spokesman Col. Gilles Jaron said that planes dropped around 60 bombs on six separate targets believed to be IS command centers or training sites. He said the strikes were designed to weaken and disorganize IS.
France has sharply increased its airstrikes in Syria following the Paris attacks.
The Charles de Gaulle nuclear-powered aircraft carrier left Wednesday for the eastern Mediterranean, which will triple France's air power in the fight against the terror group.
ksb/bw (AFP, Reuters, AP)