Twenty miners died and another 17 were missing on Friday in two separate accidents at coalmines in the east of Ukraine, an industrial region notorious for its mining safety record.

The twin disasters were the country's worst mining accidents since more than 100 miners were killed in a mine explosion in 2007.

President Viktor Yanukovych interrupted his vacation and was expected at the Lugansk mine, which is run by a private holding controlled by Rinat Akhmetov, Ukraine's richest man who bankrolled his 2010 presidential campaign.

Yanukovych also cancelled plans to attend the Formula 1 Power Boat Grand Prix near Kiev, his administration said.

At least 16 miners were killed instantly as a result of an explosion at the Sukhodolskaya-Vostochnaya coalmine in the eastern Lugansk region early Friday, the emergencies ministry said.

Another three workers received burns and other injuries and were hospitalised, it said. One of the injured died later of his wounds.

The two injured were in a grave condition, said Pavel Malysh, top health official for the Lugansk region, noting they suffered from a combination of burns and head injuries.

"We're are doing our best to save them," he said.

"The fate of nine miners remains unknown," said the Kiev-based emergencies ministry in a statement, adding that a total of 28 people were working at the pit when the explosion occurred at 1:57 am Friday.

The Lugansk regional administration, citing preliminary information, said the accident was caused by a methane explosion, which has caused most of the country's past mining disasters.

A separate accident at the state-controlled Bazhanova mine in the town of Makiyivka in the neighbouring Donetsk region left three people dead, the emergencies ministry said in a statement.

The emergencies ministry said the tragedy was caused when the 70-metre-high (230-foot) mine headframe, which is used to lower miners down into the mine and bring them up again, collapsed earlier on Friday.

Eight workers were missing, according to the emergencies ministry, and officials said it appeared they were still alive but trapped under the rubble.

"The voices of two people can be heard from under the ruins," said Donetsk region governor Andriy Shishatsky.

"They're saying that more people are under them. The main task is to get the people out as soon as possible."

Another four were injured, the emergencies ministry said, adding that more than 530 workers were able to bring themselves to the surface using emergency shafts.

An official with Metinvest Group, a private holding that includes the company operating the Lugansk region mine, said it had modern equipment but was one of the most dangerous coal mines in the country as it had high levels of methane and had experienced accidents in the past.

System Capital Management Group, controlled by Akhmetov, has a 70 per cent stake in Metinvest.

"The company spent huge money to upgrade it," the official said on condition of anonymity. "But the mine is incredibly dangerous."

Albina Kosheleva, the Lugansk regional administration spokeswoman, also said the mine boasted modern equipment and the safety procedures there were at a "decent level".

The Metinvest official said families of the miners killed in the blast would each receive one million hryvnias ($125,000).

Dmitry Kalitventsev, leader of a local miners' trade union, expressed fears the rescue teams would find more dead at the Lugansk mine.

"It is most likely that all of them died," he said, referring to the missing workers.

Deadly accidents are frequent in Ukrainian mines, most of which are located in the country's industrial eastern region. Many of the mines are underfunded and poorly equipped, while safety violations are rife.

In the worst accident of its kind in the country's post-Soviet history, more than 100 miners were killed in an explosion in 2007 at the Zasyadko mine, one of the three biggest in Ukraine.