Sudan bars SPLM-North and other 'southern parties'
Sudan has ordered 17 political parties to stop their activities, saying most of their leaders and members come from newly independent South Sudan and so are now foreigners.
Those targeted includes the SPLM-North, which was outlawed last week.
The party has strong ties to former SPLM rebels - now the ruling party in the south which seceded in July.
This crackdown follows fighting in some border states between soldiers loyal to SPLM-North and government troops.
South Sudan voted to split from Sudan in a referendum last January, following the 2005 peace deal ending decades of north-south civil war in which an estimated 1.5 million died.
A statement from the Political Parties Affairs Council said the 17 political groups were now considered "foreign parties".
"Their leadership and most members have lost the Sudanese citizenship," Reuters news agency quotes the statement as saying.
The parties have the right to establish new parties that comply with legal requirements, the state-owned Suna news agency reports.
SPLM-North has said its offices have been closed down and many of its party members arrested since violence broke out earlier this month in Blue Nile state, where a state of emergency has been declared.
Conflict erupted in South Kordofan state ahead of the south's independence in July.
Both Khartoum and the South Sudan government have strong support in these areas, which were key battlegrounds during the civil war.
Government forces have been accused of ethnic cleansing in South Kordofan, while Khartoum says the rebels are trying to start a new civil war in Sudan.
It also accuses South Sudan of supporting the SPLM-North fighters, a charge the country denies.