Troops have entered city streets and administrative and governmental buildings, as well as cultural memorials and famous buildings, are being guarded. The cities are divided into responsibility zones; in business districts, check points are being created, which can be crossed only with a special permit. Parking is being redirected near administrative buildings. Planes are patrolling the air space.
These security measures (nothing of the kind has taken place since WWII) were taken by the US just after launching the military action against Afghanistan. In his TV speech, George Bush appealed to Americans to understand the necessity of such measures. He personally obliged the governors of the states to use the National Guard to protect local public places. “To defend our nation, the government has engaged reserves," George Bush said in his TV speech, which was transmitted in the US just before the bombardments.
The choice of the city of Helsinki is not incidental as the capital of Finland had hosted US-Soviet negotiations on the limitation of nuclear stockpiles in 1969