A Congolese gynaecologist, honoured for his work with rape victims, says he dare not return home until his security is assured after narrowly surviving an assassination attempt last month.

Denis Mukwege was saved by a member of staff who died in the armed raid on his home in the eastern region of the Democratic Republic of the Congo. He then left for Stockholm with his daughters, who had been held at gunpoint inside the house.

"I can't guarantee my own security," Mukwege told Reuters during a visit to the European commission in Brussels. "As soon as I can guarantee I'll be protected I'll be back."

Mukwege, 57, is the founder and medical director of the Panzi hospital, in Bukavu, South Kivu province, where he and his staff treat about 3,000 victims of sexual violence a year. The doctor has won numerous international awards.

He said he believed the attackers wanted to kill him but he did not know why. Some media reports have speculated that the attack on his home, which is in one of the most guarded and secure areas of Bukavu, could have had political motives.

"Unfortunately, the attack was very fast," Mukwege said. "I would have a lot of difficulty as to say why and who did it. The only thing I can confirm is that they didn't want to steal anything. They stayed in the house for 20 minutes. They were waiting for me."

Mukwege criticised the Congolese government, saying an offer by the provincial governor after the attack to assign two police officers to protect him was insufficient.

His family were uncertain as to how long he would remain abroad. His nephew, Don Pepe, who lives in Leeds, in the UK, said: "I think he's very adamant that he won't be going there because of the security and there hasn't been any guarantee from the government that he will be protected.

"The government is slow in responding and the investigation hasn't been done thoroughly so it's difficult to see him going there right now without reassurance.

"But he does want to go back and resume his work at the hospital. It's a question of waiting and seeing where things are going to go."

Pepe, 35, who regards Mukwege as a grandfather, was shocked by last month's deadly attack. "It has been very difficult for the family. That's the last thing you expect a family member to go through. He's a church pastor as well as a doctor and such a nice guy."

There is pressure within Congo for officials to assure Mukwege safe passage.

Agnes Sadiki, head of the Women of South Kivu Caucus for Peace, said: "We call on the authorities … and all those involved in the cause of women to guarantee his security so that he can return to South Kivu and continue to care for women.

"If it were just up to us women Dr Mukwege would not leave because after his departure what will become of the many women who have benefited from his medical assistance?"

The European commission supports the Panzi hospital, which has been operating for 16 years. The commission said it would launch a €20m euro (£16m) programme to aid female victims of sexual assault in Congo.

Andris Piebalgs, the European development commissioner, said: "The EU condemns emphatically the assassination attempt of which the doctor and his family were victim on 25 October, as well as the murder of one of his guards."

In a blog post for the New York Times last week, Mukwege recalled the incident: "I found myself with a gun to my head, and just as the gun was loaded and ready to shoot, a member of my staff heroically intervened to save me.

"He shouted and came running to jump on this armed intruder, who turned and shot him. He fell down, I fell down, and I can't really remember what happened after that. I realised he was shot, and I saw him give his life for me. The attackers then got in the car and left.

"Neither I nor anyone in my family have been questioned about this incident in an effort to find out who is responsible. The lack of investigation is symptomatic of the indifference that prevails in my country."