- A declaration at the G7 meeting in Japan says a vote by the UK to leave the European Union would pose a "serious threat to global growth", BBC News reports.
In its final statement, the group warned that a UK exit from the EU would reverse the trend of increased global trade, investment and jobs.
The meeting brings together the world's leading seven industrialised nations.
The final communiqué set global growth as a priority for dealing with threats to the world's economy and security.
But the warning about the economic consequences of the UK leaving the European Union comes as Britain prepares for a referendum on 23 June.
Prime Minister David Cameron has been campaigning for Britain to stay within the 28-country bloc with recent polls suggesting a lead for those who support remaining within the EU.
