Two chengguan, or urban patrol officers, in Hangzhou, the capital of Zhejiang province, were injured with a knife by an unlicensed vendor, Metro Express reported on Tuesday.

According to the officers surnamed Wang, 56, and Xu, 47, they were inspecting a downtown street to keep order and found that the watermelon vendor from Henan province had no vendor's license, so they asked the man to stop his illegal business which was impeding traffic.

The vendor then suddenly attacked Wang and Xu with the knife he used to cut watermelons.

Backup officers arrived to control the vendor and the two injured officers are in stable condition in a hospital.

The case is under further investigation.