Belgium has lowered the security threat level in Brussels after nearly a week on maximum alert following the Paris terror attacks.

The country's Threat Analysis Coordination Agency reduced the threat level from level four to three, a spokesman for the crisis centre said.

A level three threat - which brings Brussels in line with the rest of Belgium - means there is a "serious, possible and probable" threat of a terror strike.

Reacting to the news, the Minister for Foreign Affairs Charlie Flanagan said "Irish citizens in Belgium are advised to exercise caution and be vigilant at all times."

Adding that for anybody travelling to Belgium "The utmost caution is advised at all times especially at airports and train stations."

Belgium raised its terror alert to level three immediately after the 13 November attacks in Paris, which killed 130 people.

A week later the capital was put on maximum alert as police searched for a Belgian suspect, as well as accomplices who were suspected of planning similar attacks in Brussels.

Police have launched several raids in Belgium over the past fortnight and authorities have charged five people with terrorism offences linked to the Paris attacks.

The reduced terror threat in Belgium comes as German police commando units arrested two people in Berlin on suspicion of planning a terror attack.

Police searched a mosque in the city's west before finding the suspects at a separate location in Berlin's south.

Officers have also sealed off an area were a suspicious car was discovered, a police spokesman said.