The European Commission pledged more than €100 million ($117 million) to help towns and cities, many of them historic tourist magnets, adapt their public spaces after a two-year wave of attacks that have killed hundreds of people in crowded areas.
"We can't stop all attacks," EU Security Commissioner Julian King told a press conference. "But we can make it harder and harder for the terrorists and others who wish us ill to carry out the attacks."
The steps include improving security barriers in crowded places, guidance on design to protect public spaces, and advice on how to protect sports and cultural events.
"We believe we can make public spaces less vulnerable without completely changing their nature as fundamentally open spaces where we gather to live our lives," King said.
He referred to a recent wave of "low-tech terrorism" where extremists have used vehicles to kill and maim civilians, most recently in August in the Spanish port of Barcelona and a nearby resort, in which 16 people were killed
A truck attack on the Bastille Day celebrations in the French city of Nice in 2016 killed 86 people, and there have been similar vehicle attacks in London, Stockholm and Berlin.
In addition to vehicles, recent attacks have sometimes involved knives, in contrast to the suicide bombs and automatic weapons used in previous attacks.
The plans unveiled by the European Commission, the executive arm of the 28-nation bloc, also calls for restricting access to substances used to make home-made bombs such as those used in the 2016 Brussels airport and metro attacks.
The commission also proposed a "new toolbox" of techniques and training to tackle the problem of encrypted messages used by extremists to plot attacks.
It also urged member states to support opening negotiations with Algeria, Egypt, Israel, Jordan, Lebanon, Morocco, Tunisia and Turkey on the transfer of personal data between Europol and these countries to prevent and combat terrorism and serious crimes.
It also recommended that Brussels open talks on a revised deal with Canada to share air passenger data that was ruled illegal by a top court in July.
The commission also proposed a plan step up preparedness against the "low" risk of chemical, biological, radiological and nuclear attacks, including creating a security network on the issue.