In response to the 11 March Madrid attacks, they also invoked a solidarity clause that commits EU states to assist any member hit by "terrorism", without waiting for the provision to take legal effect in a stalled EU constitution.
"There will be neither weakness nor compromise of any kind when dealing with terrorists. No country in the world can consider itself immune. Terrorism can only be defeated by solidarity and collective action," they said in a declaration.
The leaders endorsed the appointment of former Dutch deputy interior minister Gijs de Vries, 48, as the EU's first "counter-terrorism" coordinator, a new role intended to cut through red tape and ensure smoother cooperation.
The Madrid train bombings, which killed 190 people and wounded almost 1900, highlighted shortcomings in EU action against "terrorism" since the devastating September 11 attacks.
"We in the European Union must ensure that everything that can be done is done to protect our people," Irish Prime Minister Bertie Ahern told a news conference after chairing the first session of the summit. "The aim is to make the fight against terrorism more effective."
Leaders of the 25 present and future EU states called for the implementation by June of measures already agreed such as a Europe-wide arrest warrant to replace lengthy extradition procedures and joint investigation teams, some of which are still not in force in all member states.
They set short deadlines for adopting legislation in the works on compensating victims of terror and asked the European Commission to set aside funds to support victims of "terrorist" acts.
"We in the European Union must ensure that everything that can be done is done to protect our people"
prime minister, Ireland
EU foreign policy chief Javier Solana was asked to present proposals by June on how to increase the exchange of sensitive intelligence between national security services and boost operational cooperation in the hunt for "terrorists".
The leaders also called for better port security, better protection for public transport and common rules for how long telephone and Internet service providers must keep records.
It was also agreed to speed up the use of biometric data in visas and European passports and to quicken work on a database of all visas issued to non-EU citizens, seen as key to boost security and the fight against illegal migration.
The leaders backed a tougher drive to cut off suspected sources of "terrorist" finance, including better control of funds transmitted through charities and informal remittance transfer networks.
They also called for reinforcement of international cooperation with non-EU states and the need to attack the root cause of "terrorism".