"Additionally, the United States is seeking support for a UN Security Council embargo on all arms flows into South Sudan and we urge all UNSC members to join us in supporting this action".
US law requires companies, entities or manufacturers seeking to export controlled products to register with the Directorate of Defense Trade Controls, an office in the Bureau of Political-Military Affairs at the Department of State.
South Sudan's opposition is threatening to resort to "guerrilla warfare" if peace talks in Ethiopia fail in the coming days as government forces advance on remaining rebel strongholds in the fifth year of civil war. Officials say more than a million South Sudanese are on the brink of starvation, 2.4 million refugees are fleeing to neighboring countries and almost 2 million have been internally displaced.
"The Department of State today announces that it is implementing restrictions on the export of defense articles and defense services into South Sudan", State Department spokeswoman Heather Nauert said in a statement.
Amid the growing regional and worldwide pressures, South Sudan's government on Friday pledged readiness to participate with an open heart in the upcoming peace revitalization talks in the Ethiopian capital, Addis Ababa. She also encouraged the African Union and IGAD East African group to consider sanctions against those undermining peace efforts.
The US imposed sanctions on three senior officials in September previous year. We hope that the leaders of South Sudan will make peace and allow for the country to be rebuilt so that these people can go back whenever they chose to do so. "We can not stand by idly as innocent civilians are murdered and raped".
Nauert urged South Sudan's neighbors and other countries to take similar measures.
Independent UN experts have reported to the UN Security Council that South Sudan's government has spent millions of dollars on weapons as the country slid into starvation and an economic crisis.
South Sudan gained independence in 2011 but fell into a civil war in 2013, with tens of thousands killed and almost 4 million displaced since.
Last year, the United Nations experts said: "Weapons continue to flow into South Sudan from diverse sources, often with the coordination of neighboring countries".