Seven people have been arrested in Belgium and Paris after masked anti-terror police carried out a string of raids across Europe in connection with the Brussels massacres and a new terror plot.
Armed police swooped on properties in the Schaerbeek and Jette districts of Brussels and arrested a total of six people, who are thought to be connected to the airport and Metro.
Gunfire, grenades and explosions were all reportedly heard as police conducted the raids.
Meanwhile, a Frenchman was arrested during an anti-terror raid in the northern Paris suburb of Argenteuil over a planned terrorist attack which was in the "advanced stages", officials said.
French interior minister Bernard Cazeneuve said the man detained could be part of a high level terror network that was planning to strike on French soil. They "planned to hit our country", he said.
But Mr Cazeneuve said there was currently no "tangible" link between the man arrested in Paris and the attacks in Brussels.
It is understood the man detained in Paris had been under police surveillance for "quite some time".
"The arrest is the result intricate work carried out over the last few weeks by intelligence services," said Mr Cazeneuve.
He confirmed the man arrested was of French nationality and was "involved in the plot at a high level" and was "involved in a terrorist network that was ready to attack France".
Homes in the area have now been evacuated and several streets have been closed to traffic as the major police operation continues in darkness. Bomb disposal units are also at the scene.
It is understood more than 50 residents, including many children, are among those evacuated.
One resident told Le Parisien: "We saw many [police] arrive around 5.30pm. The police told us to stay at home without giving more explanation.
"Agents are hooded. Given the context, people are afraid. My son once told me he did not want to go to school tomorrow."
France has been on high alert since the November 13 attacks in Paris that killed 130 people and injured hundreds more.
Mr Cazenueve said there had been 75 arrests since the beginning of the year and 28 suspects had been jailed.