A "degree of fear" is needed for "self-preservation", the chairman of a campaign for the UK to remain in the EU has said.
Launching the Wales Stronger in Europe campaign, Geraint Talfan Davies said events around the world mean there was "a lot to be frightened of".
He was responding to the suggestion the Remain campaign was using fear as a tactic to persuade voters.
The Leave campaign insisted the future would be "brighter" outside the EU.
Mr Davies said: "When I look around the world there's quite a lot to be frightened of.
"You've got a mini world war going on in the Middle East.
"You've got the biggest movement of people since the second world war.
"You've got Vladimir Putin engaged in subtle military ways in the Ukraine and also trying to unsettle the whole of Europe.
"Having a reasonable degree of fear is realistic and is the best way to self-preservation."
But Sam Gould from Grassroots Out disagreed: "Everyone's future will be brighter when we leave the European Union.
"The fact is we'll be able to have control over our own laws. We'll be able to make our own decisions.
"We'll be able to control funding in the UK, rather than let unelected, unaccountable bureaucrats in Brussels spend our money."