At 21:00, 17 June, the two assault trenches towards the Tongeren Gate were opened. Work progressed at a steady pace under the cover of darkness and already in the late night a start could be made with the first parallel, their connecting trench, which was finished the next day. During 19 and 20 June, the second parallel was constructed. De Fariaux considered a sally to destroy the trenches but decided against it because they were too extensive and had been reinforced by artillery. The French gun batteries smashed the palisades, silenced the Dutch cannon on the Tongerse Kat, and created small breaches in the main wall. This caused much nervousness among the city population, as traditionally soldiers had the right to plunder a city once its wall had been breached. On 23 June, the left and right assault trenches reached their farthest point, about 160 metres from the forward defences, beyond effective musket range. During the night of 23/24 June, the third parallel was finished and about 2500 troops were assembled in it to storm the gate.