KIEV (Reuters) - Ukraine held memorial services on Tuesday to mark the 30th anniversary of the Chernobyl nuclear disaster which permanently poisoned swathes of eastern Europe and highlighted the shortcomings of the secretive Soviet system.

In the early hours of April 26, 1986, a botched test at the nuclear plant in then-Soviet Ukraine triggered a meltdown that spewed deadly clouds of atomic material into the atmosphere, forcing tens of thousands of people from their homes.

President Petro Poroshenko attended a ceremony at the Chernobyl plant, which sits in the middle of an uninhabitable 'exclusion zone' the size of Luxembourg.

"The issue of the consequences of the catastrophe is not resolved. They have been a heavy burden on the shoulders of the Ukrainian people and we are still a long way off from overcoming them," he said.

More than half a million civilian and military personnel were drafted in from across the former Soviet Union as so-called liquidators to clean-up and contain the nuclear fallout, according to the World Health Organization.