China has asked countries participating in this year’s G20 summit in the Chinese city of Hangzhou to provide lists of possible terror groups and terrorists who might target the meeting.

The summit, expected to be held in early September, will gather major world leaders together like Chinese President Xi Jinping and U.S. President Barack Obama.

A senior Chinese counter-terrorism official said China is facing a grim task in fighting terrorism, and sought participating countries’ cooperation to ensure the safety of such large-scale meetings.