(CNN) -- Rebels in the Democratic Republic of the Congo took control Tuesday of the city of Goma, including its airport and the border with Rwanda, after days of clashes, a Congolese reporter on the ground said.


The M23 rebel group, which has been engaged in heavy fighting with Congolese army forces, has also taken control of the government radio station, said the reporter, who can't be named for security purposes.

M23 rebels were seen walking through town and entering government and police buildings, he said.

Groups of fighters talked to local people as they emerged from their places of hiding when the clashes stopped. Many residents had spent hours hunkered down in their homes, listening to the small arms and heavy artillery fire from several directions.

A group of the rebels continued to fight with government soldiers as they fled west of Goma, the capital of North Kivu province.

MONUSCO, the U.N. peacekeeping force, is still present in Goma. It has largely kept out of the fighting in recent hours.

An M23 rebel spokesman, calling his group the Revolutionary Army of Congo, went on the radio Tuesday afternoon to address the people of Goma.

Lt. Col. Vianey Kazarama said the group was there to protect the population and that people should return to work on Wednesday.

Any pockets of the army left should join the rebels or they will fight against them, Kazarama said. He called on members of the police and army still in Goma to meet with the rebel leadership Wednesday morning to "discuss" with them, and to hand over their weapons and uniforms and join the rebels' cause.

The group has already started recruiting new members at the police headquarters in Goma, according to the Congolese reporter at the scene.

Local radio stations, often the main source of information, had gone off the air earlier Tuesday.

The noise of heavy shelling and gunfire echoed through the previous night in Goma after a 24-hour deadline given by M23 to negotiate expired. Local independent radio stations reported that the Congolese government refused to meet the deadline.

The conflict spread over the border Tuesday when several shells hit Rwanda, killing two and injuring several others, Rwanda's Foreign Minister Louise Mushikiwa said in an interview with CNN.

"We have had to be very restrained in this latest flare-up," she said.

Several high-ranking government officials have fled Goma for nearby Bukavu, in South Kivu, U.N. officials and a senior NGO official said earlier Tuesday.

The local Goma government could not be reached for comment. Nor could MONUSCO, which is mandated to protect civilians in Goma.

The eastern part of the Democratic Republic of the Congo has been embroiled in violence since 1994, when Hutu forces crossed the border fearing reprisals following the genocide in neighboring Rwanda.

Soldiers from the M23 group were part of the national army as part of peace negotiations brokered in 2009. They broke away from the Congolese army in April, complaining about a lack of pay and poor conditions.

One of its commanders, Bosco Ntaganda, is wanted by the International Criminal Court for war crimes, including recruiting child soldiers.

Security analysts say the rebellion in eastern Democratic Republic of the Congo has dangerous regional implications, and the international community has expressed alarm at the M23 advances.

British Foreign Secretary William Hague condemned M23's advance into Goma and said anyone responsible for rights abuses would be held to account.

"The M23 must withdraw their forces immediately and allow legitimate government control to be restored. The cessation of hostilities and the protection of civilians is paramount," he said in a statement.

International Crisis Group, an independent anti-conflict NGO, also warned that "the fall of Goma could lead to serious human rights abuses against civilian populations."

The settling of scores or even extrajudicial killing of members of the authorities and civil society activists who have opposed M23 could fuel further violence, it said on its website.

The unrest could also spread to neighboring communities and "relaunch open warfare between the DRC and Rwanda," it said.

The United Nations and some donor countries have accused neighboring Rwanda of backing the M23 rebel group by providing it with arms, support and even soldiers.

It is an allegation that Paul Kagame, Rwanda's president, has repeatedly denied.

"As far as Rwanda is concerned, we have moved way past these accusations of our involvement," Mushikiwa said. "We need to talk solutions of how to get out of this situation."

She added that Rwanda would not engage in any talks with M23. "Our interlocutor is the government of the DRC," she said.

Mushikiwa said that Rwanda would close the border crossing if asked to by the Congolese government, but that such a move could have humanitarian consequences.

Tens of thousands of Congolese, already displaced by previous rounds of fighting in the volatile region, have fled camps around the edges of Goma, according to UNICEF and Doctors Without Borders.

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