The US government's hope on Uganda, Kenya, Ethiopia and Sudan to lead the way in enforcing an arms embargo against South Sudan will be tested by deeply rooted vested interests in the region.
The Juba administration seems confident that it would take more persuasion and threats of other punitive measures for the Inter-Governmental Authority on Development (Igad) states to act against it.
"We are a member of Igad and the East African Community, and we have our internal regulations and laws," Vice President Gen Taban Deng Gai said in Juba after the US imposed the arms embargo on February 2.
The US State Department restricted the sale of defence equipment to the country, and urged the United Nations and other countries to follow suit. US ambassador to the UN Nikki Haley said the measures are meant to reduce the violence in South Sudan, slow the flow of arms and ammunition and protect innocent lives.
Spokesperson for the US Embassy in Juba Mark Weinberg told The EastAfrican that in addition to targeted sanctions on those who foment violence and obstruct the peace process, the Trump administration is also urging all countries not to facilitate the actions of persons or entities that are destabilising the country.
"We urge all countries, including South Sudan's neighbours to cut off the flow of arms into the country. We hope that our example will encourage the international community to include a United Nations Security Council Resolution that would also impose a multilateral embargo on all arms flowing into South Sudan," said Mr Weinberg.
But for the past two years, Russia and China -- two permanent members of the United Nations Security Council with veto power -- have stood in the way of approving the arms embargo, sponsored by the US.
Indeed, Juba has openly said that the US is no longer their partner and have recalled their ambassador to Washington, Garang Diing.
President Salva Kiir's government is also questioning President Trump's commitment to making peace in South Sudan. The country's ambassador to the African Union James Morgan told The EastAfrican that the US has made it difficult for the ongoing Igad talks in Addis Ababa to conclude.
"The embargo will embolden the rebels knowing that the US is on their side," said Mr Morgan.
But South Sudan observers say that rebels aligned to former vice president Dr Riek Machar have been struggling to procure arms after Khartoum, which was initially sympathetic to their cause, decided to halt the flow of arms in order to secure the lifting of the 20-year economic sanctions.
Kenya -- whose Mombasa port is the main entry for arms destined for South Sudan -- has remained cagey on the issue. In 2016, Uganda's President Yoweri Museveni opposed a UN plan to impose an arms embargo on South Sudan, saying it would weaken its army just as the country was trying to contain a resurgence of violence.
Diplomatic sources say that the US is looking to rely more on Ethiopia -- which is their main ally in the region in the war against terror -- to enforce the embargo. But Addis Ababa is also cautious not to be seen to be interfering with South Sudan's sovereignty, having recently signed a defence pact with Juba.