The US administration is pressing the 27 governments of the European Union to sign up for a range of new security measures for transatlantic travel, including allowing armed guards on all flights from Europe to America by US airlines.

The demand to put armed air marshals on to the flights is part of a travel clampdown by the Bush administration that officials in Brussels described as "blackmail" and "troublesome", and could see west Europeans and Britons required to have US visas if their governments balk at Washington's requirements.

According to a US document being circulated for signature in European capitals, EU states would also need to supply personal data on all air passengers overflying but not landing in the US in order to gain or retain visa-free travel to America, senior EU officials said.

And within months the US department of homeland security is to impose a new permit system for Europeans flying to the US, compelling all travellers to apply online for permission to enter the country before booking or buying a ticket, a procedure that will take several days.

The data from the US's new electronic transport authorisation system is to be combined with extensive personal passenger details already being provided by EU countries to the US for the "profiling" of potential terrorists and assessment of other security risks.

Washington is also asking European airlines to provide personal data on non-travellers - for example family members - who are allowed beyond departure barriers to help elderly, young or ill passengers to board aircraft flying to America, a demand the airlines reject as "absurd".

Seven demands tabled by Washington are contained in a 10-page "memorandum of understanding" (MOU) that the US authorities are negotiating or planning to negotiate with all EU governments, according to ministers and diplomats from EU member states and senior officials in Brussels. The Americans have launched their security drive with some of the 12 mainly east European EU countries whose citizens still need visas to enter the US.

"The Americans are trying to get a beefing up of their visa-waiver programmes. It's all contained in the MOU they want to put to all EU member states," said a diplomat from a west European country. "It's a very delicate problem."

As part of a controversial passenger data exchange programme allegedly aimed at combating terrorism, the EU has for the past few months been supplying the American authorities with 19 items of information on every traveller flying from the EU to the US.

The new American demands go well beyond what was agreed under that passenger name record (PNR) system and look certain to cause disputes within Europe and between Europe and the US.

Brussels is pressing European governments not to sign the bilateral deals with the Americans to avoid weakening the EU bargaining position. But Washington appears close to striking accords on the new travel regime with Greece and the Czech Republic. Both countries have sizeable diaspora communities in America, while their citizens need visas to enter the US. Visa-free travel would be popular in both countries.

A senior EU official said the Americans could get "a gung-ho frontrunner" to sign up to the new regime and then use that agreement "as a rod to beat the other member states with". The frontrunner appears to be the Czech Republic. On Wednesday, Richard Barth of the department of homeland security was in Prague to negotiate with the Czech deputy prime minister, Alexandr Vondra,

Prague hoped to sign the US memorandum "in the spring", Vondra said. "The EU has done nothing for us on visas," he said. "There was no help, no solidarity in the past. It's in our interest to move ahead. We can't just wait and do nothing. We have to act in the interest of our citizens."

While the Czechs are in a hurry to sign up, Brussels is urging delay in order to try to reach a common European position.

"There is a process of consultation and coordination under way," said Jonathan Faull, a senior European commission official involved in the negotiations with the Americans.

To European ears, the US demands sound draconian. "This would oblige the European countries to allow US air marshals on US flights. It's controversial and difficult," an EU official said. At the moment the use of air marshals is discretionary for European states and airlines.

While armed American guards would be entitled to sit on the European flights to the US, the Americans also want the PNR data transfers extended from travellers from Europe to the US to include the details of those whose flights are not to America, but which overfly US territory, say to central America or the Caribbean.

Brussels has told Washington that its demands raise legal problems in Europe over data protection, over guarantees on how the information is handled, over which US agencies have access to it or with whom it might be shared, and over issues of redress if the data is misused.

The Association of European Airlines, representing 31 airlines, including all the big west European national carriers, has told the US authorities that there is "no international legal foundation" for supplying them with data about passengers on flights overflying US territory.

The US Transport Security Administration has also asked the European airlines to supply personal data on "certain non-travelling members of the public requesting access to areas beyond the screening checkpoint".

The AEA said this was "absurd" because the airlines neither obtain nor can obtain such information. The request was "fully unjustified".

If the Americans persevere in the proposed security crackdown, Brussels is likely to respond with tit-for-tat action, such as calling for visas for some Americans.

European governments, however, would probably veto such action, one official said, not least for fear of the "massive disruption given the huge volume of transatlantic traffic".