By Crispin Kyala

BUKAVU, Democratic Republic of Congo, Jan 15 (Reuters) - A Congolese court has sentenced three Chinese citizens to seven years in prison after they were arrested in possession of gold bars and $400,000 in cash and found guilty of illegal activities linked to the artisanal mining sector.

The trio are the first Chinese nationals to stand trial since Democratic Republic of Congo launched its latest push to crack down on the unlicensed extraction of the many precious and strategic minerals buried in its conflict-torn east.

"This is an educational trial that should normally serve as a wake-up call to all Chinese nationals who think they can leave China, arrive in Kitutu, Kibe, Lugushwa, Kamituga or Mwenga and behave as if they were in their own room, without even paying the hotel fees," said Christian Wanduma, a lawyer representing local communities in the trial.

The judge in a court in Bukavu, the capital of eastern South Kivu province, found the defendants guilty on Tuesday of money-laundering, illegal purchase and possession of mineral substances, and other charges.

In addition to the prison sentence, the judge ordered them to pay a fine equivalent to $600,000, and permanently banned them from Congo once their sentences are served.

He acquitted them of charges including fraud and illegal mineral extraction for lack of evidence. The defendants had pleaded guilty to four of the seven charges against them, but said throughout the trial that they had not known they were breaking Congolese law before they were arrested on Jan. 4.

Their lawyers said they would appeal the ruling.

Congo has struggled to stop unlicensed companies and local armed groups exploiting its rich reserves of cobalt, copper, gold and other minerals.

Protesters took to the streets of Bukavu last week after Chinese men arrested on suspicion of illegal mining in a separate case were released.

"Our minerals are being plundered by companies that are mostly Chinese-owned and our people remain in extreme poverty, the roads are very dilapidated, we have difficulty accessing drinking water, health care, education, electricity, employment," civil society leader Nene Bintu said at the demonstration.

"This situation has gone on for too long and must end now."

In 2021, the authorities banned six small Chinese-owned mining companies, who it accused of operating illegally.

(Additional reporting by Sonia Rolley Writing by Alessandra Prentice and Portia Crowe Editing by Ros Russell)

((alessandra.prentice@thomsonreuters.com;))