Police are the "fists and daggers" in the fight against terrorism, China's President Xi Jinping said on a trip to the western Xinjiang region where authorities say members of a Muslim minority are waging a violent separatist campaign.

Xi's tour, reported in state media late on Monday, was his first to the region since a November meeting in which he ushered in a national security commission to combat foreign and domestic threats.

Xi has raised the pitch of his warnings on security threats after a spate of deadly attacks, including one in the southwestern city of Kunming in March in which 29 people were killed and 140 injured by knife-wielding attackers who the government said were militants from Xinjiang.

"The Kashgar region is the front line in anti-terrorism and maintaining social stability," the official Xinhua news agency citied Xi as telling paramilitary police in the Silk Road city of Kashgar in western Xinjiang that has been at the center of much of the unrest.