The committee said the cause of the latest violence was still under investigation and did not specify which tribes were involved in the clashes in two parts of the state.
In an overnight statement, it announced a curfew in two major cities, and banned unnecessary gatherings.
"The regrettable tribal clashes renewed on Thursday afternoon... without any clear reasons and despite sincere efforts by the government to stop hostilities," the official SUNA news agency reported, quoting a statement by security services in Blue Nile state.
The clashes left "seven people killed and wounded 23 others", it said, noting that the violence was centred in East Ganis village and the Roseires area.
In mid-July, at least 105 people were killed and thousands displaced in fighting over land between the Hausa and Funj tribes, and unrest spread to other states.
Tensions boiled over in July following accusations from the Funj, who have long inhabited Blue Nile state, that the Hausa, who inhabit farming areas across the country, were trying to lay claim to parts of their land.
Fighting in the region pitted Hausa tribes against rival communities including the Berta people, leaving at least 105 people killed and dozens wounded.
The clashes at the time erupted after Hausa tribes requested the creation of a "civil authority", which rival groups saw as a means to gain access to land.
The violence displaced some 31,000 people, many of whom sought refuge in schools turned into displacement camps.
The clashes also triggered angry protests across Sudan, with the Hausa people demanding justice for those killed.
There has also been sporadic violence in eastern coastal regions and western Darfur despite a nationwide peace deal signed by some rebel groups in Juba in 2020.
Protesters have accused Sudan's military rulers of failing to protect civilians and stoking tribal conflict.
Military leaders, who seized power in October 2021 saying they wanted to preserve the country's stability, have said they are working to shore up the peace deal and improve security.
This report was prepared with information from Agence France-Presse and Reuters.