Lebanon is to observe the first anniversary of the deadly blast that struck Beirut port on August 4 last year as a national day of mourning, the prime minister's office said. The explosion sparked an outcry from international allies and the Lebanese, who blamed the country’s entrenched political class, already accused of failing to remedy a severe economic crisis, of criminal negligence. Caretaker prime minister Hassan Diab, who resigned after the blast but whose Cabinet has yet to be replaced, signed a draft decree on Friday to mark the date as a national day of mourning. The order will require President Michel Aoun's approval for it to take effect. “I say, in full transparency, that the rampant corruption that tightens its grip on the state is primarily responsible for the port explosion,” Mr Diab said during a meeting with the families of the victims. “We should know the entire truth about this explosion. The martyrs will not rest in peace unless the truth is revealed.” Tatiana Hasrouty, whose father was killed in the explosion, says the gesture is not enough for the families of the victims, who have been seeking answers and justice for the past 10 months. "Declaring the 4th of August a National day of mourning by the people who caused the mourning is ironic," Ms Hasrouty said. "The 4th of August is a yearly reminder to the people in power that they failed, that they are criminals. The only positive step I want is Justice, people taking accountability for their actions. When justice prevails, the Lebanese people will be relieved of its corrupt state." The investigation into the case continues, 10 months after the incident. The blast was caused by the detonation of thousands of tonnes of ammonium nitrate – a fertiliser also used in making explosives – that had been stored at the port for years, creating one of the largest non-nuclear explosions in the world. More than 200 people were killed, at least 6,500 injured and large areas of the city were destroyed in the blast, leaving millions of residents traumatised. The circumstances that led to the dangerous chemicals being seized and stored at the port in 2013 while en route from Georgia to Mozambique, are not clear. A initial report on the causes of the blast, ordered to be submitted within five days of the incident, was never delivered. The investigating judge, Fadi Sawan, was removed from the case in February after he summoned powerful politicians for questioning, all of them close to Hezbollah, the powerful Iran-backed Lebanese party and militia. Mr Sawan had charged Mr Diab, former finance minister Ali Hassan Khalil and former public works ministers Yusef Fenianos and Ghazi Zeaiter with negligence in December. Lebanon’s court of cassation replaced him in February after a request filed by Mr Khalil and Mr Zeaiter.