Immigration boosts economies but can cause social tensions and security concerns, the International Monetary Fund (IMF) said on Tuesday, at a time when high immigration levels are contentious in the U.S. and Europe.

A one percentage point increase in the share of migrants in the adult population could increase gross domestic product (GDP) per capita in host countries by around 2 percent in the long-run, the IMF said. GDP per capita is a measure of average income per person, so this would imply that long-standing citizens as well as newcomers gain from immigration. This occurs because in the long-term, immigration increases labor productivity, which in turn raises income levels, according to the IMF.