Nasr enlisted the aid of the rulers of Bandar Rig, Bandar Ganaveh and Dashtestan and amassed an army of 2,000 soldiers to be commanded by his nephew, Mohammed. The Persians launched an assault of Zubarah's fort but were forced to break the siege after suffering stiff resistance from the Al Khalifa defenders and facing imminent naval reinforcements from Bani Utbah men in Kuwait. In retaliation to the assault, the Bani Utbah clan launched an invasion of Bahrain Island in 1783. Historians disagree on who attacked first; some historians believe that the incoming naval reinforcements from Kuwait intercepted a message from Nasr Al-Madhkur to his representative in Bahrain stating that the Persians had lost the battle. Upon learning this, the fleet switched course and invaded Bahrain, capturing the Bahrain fort and surrounding the Persian garrison. With a large coalition of tribesmen from the Bani Utbah and interior Arabia, the invasion of Bahrain was completed on 28 July 1783 Other historians believe that the Kuwaitis invaded Bahrain because they were closer to it than to Zubarah and as such, would deliver a tactical defeat to the Persians and would later handover possession to the Bani Utbah clan. The most probable version, as put forward by Historian J. G. Lorimer, was that the invasion was led by Ahmed Al Fateh in 1783 and that he defeated Nasr Al-Madhkur in battle on the outskirts of Manama and plundered the town.Historians dispute the date of the invasion, some stating it occurred in 1782 while others say it was 1783. Ahmed al-Fateh ruled Bahrain and Zubarah, visiting the former in the summer and the latter in the winter, until his death in 1796.