European ministers have agreed to increase security on key international rail routes and improve intelligence sharing after the thwarted gun attack on a French train.
Home Secretary Theresa May and Transport Secretary Patrick McLoughlin were among representatives of nine countries at a summit in Paris called to formulate a co-ordinated response to the threat of an atrocity.
Mrs May said the attack on the Thalys service was "a shocking reminder of the threats we all face".
"Only by working together can we protect our citizens and defeat those who want to harm us," she added.
French interior minister Bernard Cazeneuve said after the talks that it was "essential to put in place co-ordinated operations on certain targeted routes".
The nations taking part include Germany, Belgium, the Netherlands, Luxembourg, Switzerland, Italy and Spain, who have agreed to "co-operate more closely still" over intelligence about the movements of suspected terrorists.