Firefighters have extinguished forest fires that were edging towards radioactive dumps in the Chernobyl exclusion zone amid warnings of a 'catastrophic' threat.

Ukrainian emergency officials said Tuesday they have extinguished the forest fires in the radiation-contaminated area, but acknowledged that grass is still smouldering in some areas.

Hundreds of firefighters backed by aircraft have been battling several forest fires around Chernobyl for the past 10 days. They contained the initial blazes, but new fires raged closer to the decommissioned plant.

Forest fires burn at night as seen from the former Chernobyl nuclear power plant in Ukraine, which exploded in a nuclear catastrophe in 1986. Ukrainian emergency officials say they have extinguished the forest fires

Emergencies Service chief Mykola Chechetkin reported to President Volodymyr Zelenskiy that rain helped firefighters put out the flames, but acknowledged it would take a few more days to extinguish smouldering grass.

Mr Chechetkin said emergency workers have prevented the fire from engulfing radioactive waste depots and other facilities in Chernobyl.

The emergencies service said radiation levels in the capital Kyiv, about 60 miles south of the plant, are within norms.

Images showed smoke blowing over the 'sarcophagus' of reactor number four, which exploded in the world's worst nuclear accident in what was then the USSR in 1986.

So-called 'crown fires' - when flames spread at great speed from treetop to treetop - were advancing through the uninhabited 'dead zone' around the plant.

One fire came within just three miles from highly radioactive dumps, according to the State Agency of Ukraine on Exclusion Zone Management.

Smoke from wildfires blows over the Chernobyl nuclear power plant, amid fears that fire is spreading quickly through the exclusion zone

This map shows where two forest fires are burning in the Chernobyl exclusion zone, one of them close to the destroyed power station

One fire was burning around Kriva Gora ghost village, on the left bank of the Pripyat River, while another was 16 miles away.

Other ground-level flames were reported as being only a mile or so away from the sarcophagus, but have since been extinguished.

Deputy interior minister Anton Herashchenko said trees had been cut down around the notorious power station to prevent 'crown fires' reaching it.

'The forest was specially cut down around the storage in order to avoid the threat of fire,' he said. 'The distance to the green is more than 100 metres (330 ft).'

He claimed an expert involved in securing radioactive waste at the site told him: 'There would be nothing to burn, even if everything there is filled with napalm.'

On Monday, activists warned that the blazes were getting dangerously close to waste storage facilities.

Yaroslav Yemelyanenko, a member of the public council under the state agency in charge of the closed zone around the plant, said one fire was raging just over a mile from one of the radioactive waste depots.

Last week, officials said they tracked down a man suspected of triggering the blaze by setting dry grass on fire in the area. The 27-year-old said he burned grass 'for fun' and then failed to extinguish the fire when the wind caused it to spread quickly.

On Monday, police said another local resident burned waste and accidentally set dry grass ablaze, triggering another devastating forest fire. They said he failed to report the fire to the authorities.

Fire and smoke over the skyline of the exclusion zone, with the dome which now covers the destroyed reactor circled on the left

The smoke as seen over an office building on the Chernobyl site. The Ukrainian government has insisted there is no danger to the plant

Yuhimenko alleged that the fires in Red Forest and near the Vector storage facility could be the work of arsonists.

'There are clear facts - the Chernobyl zone began to burn in different places almost simultaneously. This does not happen by itself,' he claimed.

'First started to burn Polesskoye, then Red Forest and almost immediately the forest adjacent to Vector.

'Sparks cannot be carried so easily by the wind, especially over such hefty distance. Fire there is a danger because radioactive aerosols rise far up through heat fluxes and can go anywhere. '

One arson suspect was reportedly detained. But Yuhimenko said: 'Our state does not react to what is happening at all.

'It seems that in Ukraine nothing happens except coronavirus. And the fact that the entire Chernobyl zone is on fire is of no interest to anyone.'

The Ukrainian government has mobilised helicopters and more than 400 firefighters, some of whom are pictured battling the forest fires

The view of the smoke from the 'ghost city' of Pripyat, with the dome of the Chernobyl power plant seen in the distance on the far left

The destroyed reactor number four was entombed in this 'sarcophagus' along with the initial containment structure

Kiev mobilised helicopters and more than 400 firefighters, with planes dropping tonnes of water on the fire in the 11 days since the first fire began.

Sergiy Zibtsev, head of the Regional Eastern European Fire Monitoring Centre, told AFP that the fire was 'super-huge' and 'unpredictable'.

President Vladimir Zelensky said he was monitoring the Chernobyl fires.

The Emergencies Ministry in Russia's Bryansk region is monitoring radiation levels but say so far they are normal.

The 1,000 square mile Chernobyl Exclusion Zone was established after the April 1986 disaster at the plant that sent a cloud of radioactive fallout over much of Europe. The zone is largely unpopulated, although about 200 people have remained despite orders to leave.

Blazes in the area have been a regular occurrence. They often start when residents set dry grass on fire in the early spring - a widespread practice in Ukraine, Russia and some other ex-Soviet nations that often leads to devastating forest fires.