Capital cities of European countries have been warned of potential shootings or bomb attacks before New Year's day. The Austrian police said on Saturday that in the days before Christmas, a “friendly” intelligence service had informed the European governments of the possible attacks.

A statement released by the Vienna police said the names of several possible attackers were mentioned to the governments, Reuters reported. Although the subsequent investigation has not yielded any concrete results so far, security across the continent has been heightened, the statement added.

The warnings come six weeks after 130 people were killed in terror attacks across Paris.