Serious terrorist offences will carry a minimum sentence of 20 years under proposals to be considered today by EU Justice and Home Affairs ministers.
Extradition for terrorist offences would become automatic within the EU and grounds for appeal would be strictly limited.
Announcing the proposals, the Justice and Home Affairs Commissioner, Mr Antonio Vitorino, said that the changing nature of terrorism meant that closer co-operation between national authorities had become essential.
"Terrorist acts are committed by international gangs with bases in several countries, exploiting loopholes in the law created by the geographical limits on investigators and often enjoying substantial financial and logistical resources. Terrorists take advantage of differences in legal treatment between states, in particular where the offence is not treated as such by national law, and that is where we have to begin," he said.
Ministers are expected to give political backing to the proposals, which define a terrorist group as a "structured organisation established over a period of time, of more than two persons, acting in concert to commit terrorist offences."
The offences covered by the measures range from murder and hostage taking to damage of public property and urban violence committed with the aim of "intimidating and seriously altering or destroying the political, economic or social structures of countries."
A spokesman for Mr Vitorino stressed that the measures would not apply to demonstrators against global capitalism such as those who clashed with police in Genoa and Gothenburg earlier this year.
But the European arrest warrant, which will replace current extradition procedures, would apply to organised criminals involved in the international drugs trade and human trafficking.
The Commission adopted the proposals yesterday as a high-level EU delegation left for Washington to discuss the fight against international terrorism.
The EU's foreign policy chief, Mr Javier Solana, the External Affairs Commissioner, Mr Chris Patten, and Belgium's Foreign Minister, Mr Louis Michel, hope to improve police and judicial co-operation between the EU and the US in the wake of last week's attacks in New York and Washington.
Mr Patten and Mr Vitorino hope to persuade EU member-states to allow Europol, the European police network, to co-operate with US law enforcement officials.
EU officials are also looking at ways of improving extradition arrangements with the US. But the Commission is adamant that the EU will not abandon its opposition to extraditing suspects to countries where they may face the death penalty.
EU leaders will discuss the fight against terrorism at an emergency summit in Brussels on Friday evening. Over dinner, they will discuss recent developments in the Middle East, which Mr Solana welcomed yesterday when he spoke to the European Parliament.
"We Europeans must carry on working to ensure that the chink of light which has appeared is maintained and expanded," Mr Solana told members of the European Parliament.
"We have to keep up the pressure and keep up our contacts on the ground so that the process can continue. Today is a day of hope," he said.
Mr Solana stressed that diplomacy was an essential part of the campaign against international terrorism in response to last week's attacks.
EU leaders believe that de-escalating the conflict between Israel and the Palestinians is crucial in preventing a backlash in the Arab world against any military action the US is planning.
Germany's Foreign Minister, Mr Joschka Fischer, was in Washington yesterday to discuss the developing situation.
The British Prime Minister, Mr Tony Blair, who has emerged as a key link between the US and other allies, will meet President Bush in the US capital today.
Despite the Commission's assurance that the new measures will not be used against political demonstrators, civil liberties campaigners may be alarmed by the range of offences covered. They include theft and the unauthorised occupation of public buildings and public spaces as well as more serious crimes such as murder, blackmail and releasing poisonous substances into the environment.
Under the proposals, even minor offences would carry a minimum sentence of two years.