Iran's Supreme Leader on Thursday claimed that the sheer scale of the coronavirus outbreak in Iran was the result of a ''biological attack'', as he issued new orders to the country's Armed Forces to join the government's fight against the disease.According to the semi-officialAli Khamenei appeared to suggest that the epidemic had been intentionally orchestrated, which provided the opportunity to rehearse a robust ''biological defense drill''.In a formal letter addressing Mohammad Baqeri, Chief of Staff of the Iranian army, the 80-year-old leader called on the military to work closely with the country's health ministry in order to build a base dedicated to preventing the spread of the disease, which has so far claimed 429 lives in the country."[The base] may be regarded as a biological defence drill, one that bolsters our nation's sovereignty and strength, particularly in light of the evidence which suggests the likelihood of a biological attack'', Khamanei wrote.While he gave no indication as to who was behind the act, Khamenei's comments echo those made by the commander of Iran's Revolutionary Guard Corps (IGRC), Major General Hossein Salami, who on March 5 speculated that the pandemic may have started a ''U.S. biological warfare attack on China''.There are currently over 11,000 cases of the novel coronavirus in the Islamic Republic, according to official figures.On Friday, Iran announced a stringent 24-hour nationwide lockdown so as to check all citizens for the virus.