SINGAPORE (AFP) - South-east Asia and Europe pledged on Friday (March 2) to speed up efforts for an elusive free trade deal, vowing to support open markets in the face of growing US protectionism under President Donald Trump.

EU trade chief Cecilia Malmstrom said a deal would "send a strong signal to the world" after Trump's plan to put tariffs on steel and aluminum sparked an outcry among American trade partners, including Europe.

Trump said on Thursday he would sign off on the measures next week, sending stock markets into a tailspin.

The 28-member European Union and 10-member Asean (Association of South-east Asian Nations) have been discussing a free trade deal for years, first launching talks in 2007 but abandoning them two years later.

The two sides last year agreed to put the deal back on the agenda and have been hammering out their positions before the process formally begins.

In the interim, the EU has struck a free trade deal with Asean member Singapore and has started talks on bilateral pacts with other states in the bloc.

"These agreements are important in their own right but they are also part of a bigger picture. We see them as building blocks on the way to broader integration," EU Trade Commissioner Malmstrom said at a forum of South-east Asian and European business executives in Singapore.

"A regional agreement between us will send a strong signal to the world, a signal that the EU and Asean... will stand shoulder-to-shoulder in support of open trade."

Malmstrom also slammed the US tariff plan and warned the EU was not ruling out taking "retaliatory measures".

"We must be very careful in using the term trade war. But it is definitely not a good development what happened yesterday," she said.

Cambodia's Minister of Commerce Pan Sorasak told the forum that an EU-Asean trade deal would be "more beneficial for all of us, especially Cambodia".

"I believe that the (free-trade deal) negotiations should relaunch as soon as possible."