Harare - Zimbabwe's war veterans, who have played a crucial and sometimes violent role supporting President Robert Mugabe, denounced him as "dictatorial" on Thursday in the latest sign of growing national instability.A series of recent street protests - the largest in many years in Zimbabwe - has been triggered by an economic crisis that has left banks short of cash and the government struggling to pay its workers.Mugabe, 92, has often used his security forces to crush dissent since he came to power in 1980 after leading the liberation war in the 1970s that ended British colonial rule.But the surge of rare public demonstrations have revealed deepening anger at the ageing president, who has vowed to stand for re-election in 2018, and at his ruling Zanu-PF party.The Zimbabwe National Liberation War Veterans' Association issued a strongly-worded statement in Harare, saying it would no longer support Mugabe in elections."The Zanu-PF party leadership has dismally failed to... address the economic problems that have beset our great nation," it said."We note with concern, shock and utter dismay the entrenchment of dictatorial tendencies, personified by the president and his cohorts which have slowly devoured the values of the liberation struggle."In February, Zimbabwean police shocked many observers by using water cannon and tear gas to prevent a meeting planned by the war veterans to air their grievances against the regime.Starting in 2000, the war veterans led the seizures of white-owned commercial farms in what Mugabe said was a reversal of imbalances from the colonial era.Worsening economic crisisThe government-supported seizures have been blamed for the drastic slump in food production that contributed to the country's economic collapse.Some veterans have also been accused of the widespread intimidation and violence during past elections that have kept Mugabe in power.This week, Mugabe shrugged off criticisms by popular pastor Evan Mawarire, who has become the figurehead of the wave of anti-government protests."I don't even know him... I don't know if he is a man of religion. A man of religion, we would hope, would preach biblical peace," Mugabe said, accusing Mawarire of being backed by foreign countries.Earlier this month, many offices, shops and some government department were closed for a one-day national strike against the country's worsening economic crisis.Last week hundreds of Mawarire supporters rallied outside a Harare court until he was released when a case of attempting to overthrow the government was dismissed.