Carrying flowers, officials lit candles for the dead at a church built to commemorate the accident. Hours earlier hundreds of Ukrainians gathered there with their heads bowed as bells tolled just after one in the morning - the time of the blast.

"The Chernobyl catastrophe should never be wiped from human memory," the government said in a state newspaper. It urged human and financial support for the people involved in the clean-up - so-called liquidators - and other victims.

"We call upon voluntary organisations, funds, every concerned citizen to show understanding and help heal the painful problems of the liquidators...those who were evacuated from their birthplaces, invalids and families who lost breadwinners as a result of the accident at Chernobyl."

The Chernobyl explosion, which killed just over 30 firefighters at the time, has been blamed for thousands of deaths due to radiation-linked illness and for a huge increase in thyroid cancer.

Dozens of women laid red carnations at the burial mound, silent and thoughtful as yet another year passes with Ukraine, neighbouring Belarus and Russia unable to overcome the consequences of the accident.

CONTAMINATED FOOD

In Belarus, thousands gathered near the centre of the capital Minsk to call for government and international help to heal the scars of the fall-out, demanding an end to food output from miles of land contamined with radioactive debris.

Struck by poverty, many in Ukraine and Belarus pick mushrooms and berries with high levels of radioactivity.

Health specialists have advised that genetic mutations and contaminated food could lead to a new generation of Chernobyl victims and prolong the tragedy for years to come.

One academic, Dmitry Hrodzinsky, also said he believed the concrete tomb now encasing the ruined reactor was unsafe, allowing radioactive dust to seep into the environment - a statement officials denied.

Officials at the plant agree the reactor needs another covering, dubbed a second shelter, but say radiation levels are decreasing and the ruined reactor poses little threat.

"Today the situation at the station is stable," Volodymyr Kholoshcha, head of the Chernobyl zone's administration, said.

Ukraine's government said it would strive to make the reactor safe, improve the lives of the accident's victims and revive contaminated lands but that it needed funds promised by the West when Chernobyl was shut down in 2000.

"We hope that the 16th anniversary of this dreadful event...will attract the attention of the world community to the global problem of...protecting the world from future (industrial and ecological) disasters," the government said.

"We believe our appeal will reach the hearts of those who understand others' sorrow."