The Prime Minister touched down at Copenhagen Airport on Wednesday ahead of the European Political Community (EPC) summit on Thursday.
Danish Prime Minister Mette Frederiksen told reporters on Wednesday that Europe is in the middle of a “hybrid war” waged by Russia and the continent must arm itself.
Ms Frederiksen told reporters: “I hope that everybody recognises now that there is a hybrid war, and one day it’s Poland, the other day it’s Denmark, and next week it will probably be somewhere else that we see sabotage or we see drones flying.”
The EPC summit will discuss continental security, with a focus on strengthening Ukraine in light of the ongoing war with Moscow.
In recent weeks European leaders have been alarmed by violations of their airspace by unidentified drones and Russian warplanes.
Several Russian drones breached Poland’s airspace on September 10, and Nato aircraft were scrambled to intercept and shoot down some of the devices.
Since then there has been a spate of drone incidents at Danish airports and military bases.
During the summit, Denmark has banned all civil drone flights, punishable by a fine or up to two years in prison.
In a statement announcing the ban, the Danish transport ministry said police were on “significantly increased alert” and that they needed to “take care of Danes and our guests”.
The ban will remain in place until October 3.
Late last month, European defence ministers agreed to develop a “drone wall” along their borders with Russia and Ukraine in an effort to better detect, track and intercept drones violating Europe’s airspace.
As he touched down, the Prime Minister greeted Joelle Jenny, the British ambassador to Denmark, by saying: “What a lovely day.”
Some 47 heads of state and government have been invited to take part in the summit, the seventh meeting of the EPC.