A verbal altrecation took place between the two sides and escalated into the raising of weapons, but a clash was prevented by SDF mediation.[73] A similar incident shortly thereafter was reported to have significantly increased tensions between the two sides.[74] Russia responded by deploying advanced air defence systems in its Qamishli airbase.[75] On 3 February, American forces attempted to block Russian patrol on the M4 highway. The Russian patrol drove around the roadblock via dirt roads and sent several helicopters to fly over American forces. US military helicopters then began pursuing the Russian helicopters until they reached Ras al-Ayn airspace.[76] A similar incident occurred on 4 February, this time with a Russian vehicle reportedly ramming a US armored vehicle which was blocking its path.