Rwandan President Paul Kagame says the UN peacekeeping force in the Democratic Republic of Congo has "in some cases" made the situation worse.
In an interview with the BBC, he said any military effort to bring peace to DR Congo needed to be "properly co-ordinated" with political efforts.
He dismissed UN allegations that Rwanda backed proxy forces in DR Congo.
The UN has nearly 20,000 peacekeepers in eastern DR Congo, where armed groups have wreaked havoc for two decades.
The UN force, now known as Monusco, first deployed in 1999 and has been widely criticised as ineffective.
It says that the peacekeepers, mandated to protect civilians and also help with the reconstruction, are spread thinly over a vast and difficult terrain.
'Chaos and displacement'
Since last year, a new rebel group, the M23, has become increasingly active in eastern DR Congo, forcing some 800,000 people to flee their homes.
Monusco came under fire for standing by as the M23 briefly took control of the key city of Goma late last year.
Asked how he viewed the record of the UN force, Mr Kagame said: "In some cases it has really become worse."
"If you see what we had last year, the resurgence of the fighting and chaos and displacement of people and so on and so forth... what we witnessed last year - actually the situation got worse."
He said that Monusco's failures had been a reason behind the formation of a UN-backed African force that will be authorised to carry out "targeted offensive operations" against armed groups.
The first contingent in the 3,000-strong force arrived in DR Congo last week.
But Mr Kagame added that "still, there are things that really don't add up".
"If you look at the problems relating to the situation on Congo, they are mainly political, they are not military... So the intervention they've, so to speak, encouraged to happen and supported, needs to be co-ordinated properly with the political efforts."
He referred to the accusation that Rwanda had backed proxy groups in DR Congo, including the M23, as "ridiculous" and "an effort to circumvent the real problem".
UN experts have cited evidence that Rwanda and Uganda are backing M23, but both countries strongly deny the charges.
Rwanda was accused of backing armed groups in DR Congo as a way to fight Hutu rebels who fled there after the 1994 Rwandan genocide.
Mr Kagame came to power as the head of a Tutsi rebel force, which ousted the genocidal Hutu leadership.
"Why would anyone blame Rwanda for a problem that has been there for the last 19 years?" Mr Kagame said.