The Democratic Republic of Congo restricted the hours of border crossings with Rwanda on Friday after a Congolese soldier was shot dead while attacking border guards inside Rwandan territory.

The Central African neighbours have been locked in a diplomatic crisis since rebels that Congo accuses Rwanda of supporting launched a major offensive in eastern Congo last month.

Rwanda denies Congo's allegations that it supports the M23 rebels, whose leadership hails from the same Tutsi ethnic group as Rwanda President Paul Kagame, or that it has sent troops into eastern Congo.

Congo's government ordered that the border with Rwanda to close each day at 3 p.m. local time (1300 GMT), several hours earlier than usual, from Friday on, according to a statement from the office of South Kivu's governor.

The border will continue to open each morning at 6 a.m., the governor's office said.

Two Rwandan police officers were wounded when the Congolese soldier crossed the border and opened fire, before an officer on duty fired back and killed him 25 metres inside Rwanda, the Rwandan military said in a statement.

Congo's government said it was investigating the incident.

(With input from Reuters)