Belarusian officials say they have taken their new Russian-built nuclear power plant offline after a generator protection system was tripped during testing procedures, marking the second minor mishap since the reactor entered commercial service in early November.

In a statement, Belarus’s energy minister said that Unit 1 as the Ostrovets nuclear plant had been “disconnected from the network after the generator protection system was activated,” in the evening hours of January 16.

The incident came “during pilot operation of Power Unit 1, as part of which the systems and equipment are being tested,” the ministry said, adding that radiation levels in the area were “normal.”

The plant, which is opposed by Belarus’ Baltic neighbors, was opened to ceremonial fanfare on November 8 by the country’s embattled authoritarian leader, Alexander Lukashenko, who declared that the former Soviet republic “will become a nuclear power.” Only three days later, the plant halted electricity production after several voltage transformers at the site exploded. The plant resumed electricity production several days later.

Neighboring Lithuania, whose capital Vilnius is only 50 kilometers from the plant, has long been opposed to the Belarusian nuclear plant, and with Estonia and Latvia, is boycotting the electricity it produces. The Baltic nation has alleged numerous safety violations at the facility and European experts hoping to investigate them have so far been rebuffed.

Why the late December visit by European officials was scrubbed remains unclear, but Belarusian nuclear officials pledged at the time that they remained “committed” and “ready” to receive the EU experts.

In a memo to European officials in December, Lithuania claimed that yet a third mishap had befallen the plant when a cooling system allegedly failed at the reactor on November 30. Lithuania also complained that the plant had come online without implementing the vast majority of EU or International Atomic Energy Agency (IAEA) recommendations, the EU Observer reported, citing the memo.

Warning that the plant could pose “significant risks” to the EU, the Lithuanian memo said that the nuclear plant’s “hasty commissioning and growing incidents indicate a real risk, which is amplified by limited management and competence abilities.”

Rosatom, Russia’s state nuclear corporation, which extended Belarus a $10 billion loan to build the plant, has denied there are safety issues, asserting in comments to Bloomberg last month that the ups and downs in power levels seen in recent weeks are a normal part of the process of bringing it into service. The company has repeatedly stated that the plant’s design conforms to the highest international standards as confirmed by the IAEA.

Still, throughout the years of the plant’s construction, numerous incidents have spooked activists and Belarus’s Baltic neighbors. Construction at the plant was delayed in 2015 when a crane operator dropped a 330-ton reactor pressure vessel, a sensitive structure that houses the reactor core, from a height of four meters.

Officials sought to cover the incident up, but it was eventually brought to light by a whistleblower. At the time, Rosatom insisted that the reactor pressure vessel wasn’t damaged, but it agreed to replace the unit at the demand of Belarusian authorities. Another reactor pressure vessel bound for the plant was accidentally run into a cement column when it was being unloaded from a rail car.

In recent months, Lithuanian authorities have handed out free iodine pills to residents living near the Belarus border. Iodine can help reduce radiation build-up in the thyroid in case of a leak of radioactivity.

The nuclear plant has also proved divisive within Belarus itself, which suffered severe damage from the 1986 Chernobyl nuclear disaster. The disaster spewed radiation across much of Europe, but Belarus was hit particularly hard by the fallout.

The plant currently operates one VVER-1200 reactor, with the second slated to come online next year.