"Europe can no longer fully rely on the United States to defend our shared values and interests, including continued support for Ukraine's sovereignty and territorial integrity," said a statement from the European People's Party, Socialists and Democrats, Renew and Greens.

"We must face this new reality and double down on our joint European effort in defence of Ukraine and European security as a whole by establishing a credible and strong deterrence against any aggression."

The call for action came after top US officials met Russian negotiators in Saudi Arabia to lay the ground for talks on ending Moscow's three-year war on Ukraine.

US President Donald Trump has sidelined Washington's allies and upended Western efforts by reaching out to Russia's Vladimir Putin.

Lawmakers said the EU must "ensure that Ukraine is in the strongest possible military position" and should enact legislation allowing it to seize over 200 billion euros ($210 billion) of Russian assets frozen in the bloc.

"There can be no negotiation about Ukraine without Ukraine and the European Union at the table. There can be no negotiation about European security without the European Union," they said.

The head-spinning moves from Washington has been coupled with suggestions from US officials that American troops could be redeployed out of Europe.

"The European Union and its Member States have no choice but to take immediate action, with NATO and likeminded non-EU allies, to invest in a more efficient and integrated European security and defence architecture," the lawmakers said.

"Our Groups recognise the sense of urgency and the need to act swiftly to secure the necessary funding for our defence policy."

European nations have ramped up defence spending since Russia launched its war on Ukraine in 2022 but admit they must move much faster to face the threat from Putin.

The EU fears that if Trump cuts a bad deal behind their backs with the Kremlin then it will leave them facing an emboldened and heavily armed Russia.