The tournament could take on immediate importance as it will offer four places in the European Championships finals.
The 54 UEFA countries will be divided into divisions with promotion and relegation and offer an extra chance to qualify for the European Championship.
UEFA's Congress in Astana voted unanimously to start the league. "This is a big step for national teams in Europe and we hope that fans will support the new format," said Wolfgang Niersbach, chairperson of the UEFA competition committee.
UEFA president Michel Platini said countries wanted a change from "the friendlies that don't interest anyone."
Though the final details have yet to be agreed, the current plan is for four divisions, which will be sub-divided into four pools of three of four teams.
Each country would play four to six matches in the first tournament between September and November 2018 -- soon after the World Cup finals in Russia.
The four pool winners would play for the title in early 2019. The pool winners will get places in the European Championship finals.
Europe's top clubs, always wary of additions to the soccer calendar, gave cautious approval to the new tournament.
The European Club Association, which groups top clubs in all UEFA member countries, said it "has taken note of UEFA's announcement."
"The European clubs do not oppose such project, as the number of international matches in the calendar remains unchanged," said an ECA statement.
"Once more details concerning the competition format are available, ECA will analyse the possible impact on club football.
ECA chairperson Karl-Heinz Rummenigge, chief executive of Bayern Munich, said: "A positive aspect of this new concept is that our players will no longer have to travel around the world for friendly matches.
"I am not worried about the Champions League; it is a prime product and the Europa League as well will continue to flourish," he commented.
The English FA strongly backed the new tournament.
"The prospect of England playing three or four teams from the best 12 or 16 countries in Europe on a home and away basis should be very exciting," said English FA general secretary Alex Horne.
"It means we will go from a major tournament such as a World Cup straight into a set of three international double-headers between September and November that will really mean something.
"There will be the threat of relegation too so there will really be something at stake."
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