France has decided to deploy 1,600 additional police officers to bolster security at its borders and on public transport following the deadly blasts in Brussels on Tuesday, French Interior Minister Bernard Cazeneuve said.

A total of 400 additional police officers will boost security in the greater Paris area, and military patrols will be refocused on public transport sites, the minister said after an emergency meeting with President Francois Hollande.

Cazeneuve said the country continued to face an "extremely high" security threat four months after the Islamist militant attacks in Paris in November that killed 130 people.

"After this morning's attacks in Brussels, I decided to deploy 1,600 extra police officers at different points across the country, at border checkpoints, and also on air, sea and rail transport infrastructure," Cazeneuve told reporters. (Reporting by James Regan; Editing by Leigh Thomas)

Meanwhile, German authorities have stepped up security measures at airports, train stations and the borders with Belgium, France, the Netherlands and Luxembourg following explosions in Brussels, a spokesman for the federal police said on Tuesday.

An additional police presence was noticeable at Frankfurt airport and train station on Tuesday morning, a Reuters eyewitness said. – Reuters