Prime Minister David Cameron took to the Huffington Post Saturday to blame corruption for many of the world’s problems and to urge fellow G7 leaders to do more than meet graft “with a reluctant sigh.”

“Whether it is the abduction of schoolgirls in Nigeria or the recruitment of fighters to the Taliban and Islamic State,” Cameron said, “time and again ordinary people are drawn to extremist groups partly as a reaction to the oppression and corruption of their own governments.”

In his HuffPo piece, Cameron said that for too long, corruption has “lined the pockets of those on the inside” but has been met with “little more than a reluctant sigh” from politicians.

“World leaders simply cannot dodge this issue any longer. We have to show some of the same courage that exposed FIFA and break the taboo on talking about corruption.”

He said he’ll put corruption at the heart of his agenda at the United Nations in September and the G20 in Turkey.

The G20 Anti-Corruption Working Group is scheduled to meet next week in Istanbul.

Cameron credited “some brave British journalists and American lawyers” for taking on FIFA and showing “that things really could change.”

Just as with FIFA, we know the [global graft] problem is there, but there is something of an international taboo over pointing the finger and stirring up concerns. At international Summits, leaders meet to talk about aid, to discuss how to grow our economies and how to keep our people safe. But we just don’t talk enough about corruption. This has got to change.

Cameron said he’ll make it his mission in the “years ahead” to fight corruption.

The migrants drowning in the Mediterranean are fleeing from corrupt African states. Our efforts to address global poverty are too often undermined by corrupt governments preventing people getting the revenues and benefits of growth that are rightfully theirs. Corruption undermines the wider global economy too. The World Economic Forum estimates that corruption adds 10% to business costs globally, while the World Bank believes some $1 trillion is paid in bribes every year.

The FIFA reforms will take time, courage, and determination, Cameron said.

“I believe world leaders must show the same courage and determination to begin a long battle against the corruption that threatens our security and prosperity across the world.”