Belarus has begun loading uranium fuel into the first of two reactors at its controversial Russian-built nuclear power plant, which has raised concerns in neighboring Lithuania and other Baltic states, the official Tass newswire reported.

The plant in Astravets – only 20 kilometers from the border with Lithuania – has been built by Russia’s state nuclear corporation Rosatom. Rosatom and Belarusian authorities have insisted that the 1,200-megawatt reactor is safe, but authorities in Vilnius, Lithuania’s capital, have described the plant as a threat to the environment and public health.

The fuel loading process will last about three months, after which the reactor will begin to generate electricity. Rosatom said construction of the plant’s second reactor will be finished by mid-2022.

Lithuania’s Energy Minister Zygimantas Vaiciunas said he had warned the International Atomic Energy Agency, or IAEA, over what he called Minsk’s haste to launch the project.

“The hurry of recent days is not compatible with nuclear safety standards,” he told reporters, according to Agence France Press.

Vilnius has banned all electricity imports from the plant, citing concerns about safety and national security, and along with Estonia and Latvia is considering slapping a fee on other power imports from Russia, as well.

Lithuania, Latvia and Estonia are moving towards a full decoupling from their Soviet-era common power system by 2025. Poland has also refused to buy electricity imports from the plant.

Belarusian officials and Rosatom itself have denied that the plant – which runs two Russian-designed VVER-1200 reactors units – posed any safety threats. In numerous statements to the press, Rosatom has insisted that the plant “fully meets post-Fukushima demands” – a reference to industry-wide safety upgrades adopted in the wake of the 2011 nuclear accident in Japan.

The construction of a nuclear plant in Belarus had been planned during Soviet times, but the efforts were abandoned after the April 26, 1986 explosion at the Chernobyl nuclear plant in neighboring Ukraine. Belarus suffered badly from the world’s worst nuclear accident, which rendered vast portions of its land uninhabitable and unsafe for agricultural production.

In total some 138,000 Belarusians living closest to the plant were evacuated, while another 200,000 living nearby moved voluntarily.

The years-long construction of the Astravets plant – financed by a $10 billion loan from Russia – was not without difficulties.

In July 2015, builders dropped a 330-ton reactor pressure vessel, a major piece of equipment housing the reactor core and cooling systems. Rosatom and Minsk managed to shut the incident up until a whistleblower leaked information to the media. Prague’s Radio Free Europe/Radio Liberty condemned the cover-up as “Soviet-like secrecy.”

Rosatom eventually agreed to exchange the dropped unit, and its replacement was delivered in May 2017. But the replacement reactor vessel then collided with a railway pylon while being transported.

On May 26, further concerns came to light when Rosatom announced that 100 workers from the plant are currently infected with the coronavirus.

The Belarusian energy ministry said it plans to add the first reactor, which has a 1.2 gigawatt capacity, to the country’s power system in the fourth quarter of this year.

The ministry said the plant will meet about one-third of Belarus’s demand for electricity, replacing 4.5 billion cubic metres of natural gas per year and reducing greenhouse gas emissions by more than seven million tons annually.