Sudan has declared a state of emergency along the border with South Sudan, signaling a continued push toward all-out war as hostilities intensify between the neighboring countries.

Sudan's official news agency SUNA reported Sunday the decree gives Khartoum broader powers to arrest and try suspects in the volatile region. It allows President Omar al-Bashir and “anyone with his mandate” to set up “special courts” to handle criminal and terror cases.

The measure also suspends the constitution in border areas and imposes a trade embargo against South Sudan. The two countries have lingering disputes over oil revenue, border demarcation and citizenship issues.

South Sudan said Sunday it will withdraw all police from the contested Abyei region.

Also Sunday, an aid group said foreigners arrested by Sudan in the contested Heglig area were de-mining the border area, contrary to claims by Khartoum they were spying for the south.

Sudan arrested a Briton, a Norwegian, a South African and a South Sudanese on Saturday in the oil-producing area.

Pro-Sudanese media quote defense officials saying the suspects were collecting “war-related” items and holding “military” material.

An official with the Norwegian People's Aid mission said one of its employees was arrested with a team contracted to de-mine the area.

The British and Norwegian embassies said Sunday they are investigating the circumstances surrounding the arrests. The detainees have been flown to Khartoum for questioning.

Sudan has accused South Sudan of using foreigners to help capture the oil-producing Heglig region earlier this month. Last week, Sudan said it has recaptured Heglig.

The international community has called on both sides to end hostilities and resume peaceful dialogue.