Nine members of the Sudan Armed Forces (SAF) were also being held, Arnu Ngutulu Lodi of the Sudan People’s Liberation Movement-North (SPLM-N), told AFP.
“Yes, we have captured them,” he said. “I want to assure you right now they are in safe hands.”
He said the Chinese have not been kidnapped and none was wounded.
They, along with the Sudanese, were captured on Saturday when the rebels destroyed a Sudanese military convoy between Rashad town and Al-Abbasiya in the northeast of the province, which has been at war since June.
Lodi said the Chinese were working mainly on road construction in the area.
They are being held in the Nuba mountains “until further notice” because of the security situation.
“Today is a little bit calm but we are expecting at any time SAF may launch an attack on us,” he said.
Spokesmen for the Sudanese army and the Chinese embassy could not be immediately reached for comment.
China is a major military supplier to the regime in Khartoum, and the largest buyer of Sudanese oil.
There is growing international concern over the situation in South Kordofan and nearby Blue Nile state, where a similar conflict broke out in September. The government is fighting ethnic minority insurgents once allied to the former rebels who now rule South Sudan.
The South gained independence from Khartoum last July after decades of civil war.
Food shortages would become critical without substantial aid deliveries into South Kordofan and Blue Nile by March, the US ambassador to the United Nations, Susan Rice, has said.
Khartoum has severely restricted the work of foreign relief agencies in the war zones.
It cited security concerns and also accused aid workers of using United Nations flights to deliver arms and ammunition to the rebels — a claim for which the UN’s top humanitarian official said there was “no evidence.”
Princeton Lyman, the US administration’s special envoy for Sudan, told reporters last week the situation is so dire Washington has warned Khartoum it would consider ways for aid to be sent in without Sudanese government approval.