KINSHASA (Reuters) - U.N.-backed government forces retook a Congolese provincial airport from rebels on Monday, an army officer said, following heavy fighting since Sunday in which two U.N. workers and several soldiers and police died.

The attack on Mbandaka, capital of Congo's northern Equateur province, marked the spread of an insurgency that began over fishing rights and underscored the central African nation's continued dependence on peacekeepers ahead of a gradual withdrawal expected to start in June.

"We have taken back control of the airport. It is now in our hands," Congolese General Janvier Mayanga told Reuters by telephone from Mbandaka on Monday. "Several soldiers and police have been killed," he said, without giving details.

Enyele rebels, who are from the country's remote north and are not linked to higher profile rebel conflicts in the east, attacked the town on Sunday and seized the airport where the world's largest U.N. mission has aircraft stationed.

Mayanga said the rebels, who mounted a series of ambushes around the airport, fled into the surrounding forest where the army was pursuing them. Peacekeepers from the U.N. mission, known as MONUC, took part in the counterattack.

"MONUC is here too -- they supported us and have done a lot of work to really help us," said Mayanga.

The U.N. mission has been central to efforts to pacify Congo since a 1998-2003 war in which millions died.

But the mission is under government pressure to start a withdrawal of its troops in June when the vast state celebrates 50 years of independence from Belgian colonial rule, and should leave completely by 2011 when it is scheduled to hold elections.

Congo, which relies heavily on revenues from its mining industry, is seeking to attract new investment to develop its promising oil reserves and is hoping to win a deal from the World Bank and IMF in the coming months to wipe out the bulk of its $11 billion in debt.

PROVINCE STARVED OF GOVERNMENT

Most of the U.N's near-22,000 peacekeepers are based in Congo's east, where they are helping the government try to oust Rwandan Hutu rebels. The force is stretched and also faces local rebellions and Ugandan rebels in the remote northeast.

"As long as insecurity persists throughout (Congo), and the Congolese government and military are incapable of resolving crises such as Equateur independent of international support, the drawdown of the U.N. mission remains premature," advocacy group Refugees International said in a report last week.

The organisation said more than 200,000 people have fled violence since a dispute over fishing rights between rival tribes flared in October and a local witchdoctor led an attack on Dongo, 100 km (62 miles) north of Mbandaka, killing hundreds.

Equateur's Vice Governor Vincent Mokako said the town had been taken by surprise on Easter Sunday when 100-150 fighters attacked as people were attending mass, and that the civilian population was still hiding in its houses on Monday.

Analysts said a long-standing row between the Enyele, a sub-tribe of the Lobala, and the Boba, may have been hijacked by groups seeking to foment trouble in the region, which was once favoured by government but is now an opposition stronghold.

"The place has been starved of any government support since Mobutu was kicked out," said a diplomat, referring to Congo's dictator Mobutu Sese Seko, who was from the province and poured money into it for decades until he was ousted in 1997.

Since Mobutu, the region's highest profile politician has been former rebel leader Jean-Pierre Bemba. Having lost to President Joseph Kabila in 2006 polls, Bemba is now awaiting trial for war crimes at the International Criminal Court.