Senegal plans to slap a fine of about 600,000 euros on a Russian ship for repeatedly fishing illegally in its waters, its fisheries minister said Sunday.

The trawler arrived in Dakar overnight Saturday under military escort after the Senegalese navy boarded the vessel off the Atlantic coast.

"The Oleg Naydenov, this big fishing boat which you see behind me and which is 120 metres long ... was fishing fraudulently, without any authorisation in Senegalese waters," minister Haidar El-Ali told the press at Dakar's Marine pier.

The ship is currently "in the hands of the Senegalese government, under the control of the national navy and the national police," he added.

Senegal can seize the ship and its cargo and impose a maximum fine of 200 million CFA francs (nearly 305,000 euros/$414,000) for the offence, said the minister.

But because the Oleg Naydenov is a repeat offender, it "will be fined twice as much, 400 million CFA francs".

Senegal "can also take this case to the courts because (the ship's captain) would not obey" orders before the Oleg Naydenov was boarded by the navy.

"This only made it worse ... They are thugs and we will fight these thugs," said the minister.

During his visit, armed soldiers could be seen on board the vessel and nearby.

Russia's Ria Novosti news agency said the ship had 62 Russians and 20 Guinea Bissau nationals on board.

On Sunday, journalists could see three Russians and several African sailors but were neither allowed to speak to them nor board the trawler.

Ali said the ship had first been spotted in Senegalese waters by a French military plane that assists the country's DPSP fishing control and protection agency.

It was stopped off southern Senegal, "in a joint area which we share with Guinea-Bissau". Senegal then sent a "commando which forced them to come here" to Dakar, after the captain would not obey orders.

Ali said Senegal was planning to adopt a decree so foreign ships "that pillage our resources can be seized and become Senegalese state property".

He also quoted a US Agency for International Development figure that put Senegalese losses because of illegal fishing at 150 billion CFA francs a year.

"There are about 50 such ships operating off our coast, entering (Senegalese territorial waters) fraudulently from time to time. We will not allow this," said Ali.

Senegal has for years been battling to contain unauthorised fishing by foreign trawlers in its waters, which has been blamed for depleting fish stocks, undermining the environment and endangering the livelihoods of local small-scale fishermen.