The leaders of the world's largest economies stuck to a goal of lifting their collective output by an extra 2 percent by 2018, even though growth remains uneven and weaker than expected globally, they said in a statement Monday.

In their final communique from a summit in Turkey, the leaders of the Group of 20 also endorsed plans to address the refugee crisis, taxation, climate change, cybersecurity and inequality, signs the grouping is increasingly willing to widen its focus beyond hard economic issues.

"We remain committed to achieving our ambition to lift collective G20 GDP by an additional 2 percent by 2018," the leaders said.