President Barack Obama has identified a new threat that he says "constitutes an unusual and extraordinary threat to the national security and foreign policy of the United States," but it isn't a new militant group in the Middle East or maneuvering by a rival superpower: It's the landlocked African nation of Burundi.

On Monday, after months of political unrest and a violent weekend that saw five people killed and reports of mortar shelling in Burundi's capital Bujumbura, Obama signed an executive order that imposes sanctions on several top Burundian officials. Obama officially declared a national emergency in the US, saying Burundi's peace and security are threatened. The president specifically underscored the "killing of and violence against civilians, unrest, the incitement of imminent violence, and significant political repression," as cause for concern.

The unrest in Burundi kicked off in April when President Pierre Nkurunziza announced plans to seek a controversial third term in office. At the time, critics argued that the 51-year-old leader was ineligible to extend his tenure in power due to the two-term limit outlined in the country's constitution, which was established in 2005 after more a decade-long civil war. The nation's high court ultimately cleared Nkruniziza to run, ruling that he had been appointed to his first term rather than democratically elected.

The reelection campaign sparked clashes in the streets of Bujumbura between Nkurunziza's opponents and supporters, with violent crackdowns against demonstrators carried out by a police force largely loyal to the president. Since the leader's electoral victory in July, murders and assassination attempts have become a fairly regular occurrence in the capital, frequently targeting members of the political opposition, human rights defenders and their families, government officials, and local journalists.

The US sanctions target four current and former Burundian officials from both sides of the crisis, including former general Godefroid Niyombare and former defense minister Cyrille Ndayirukiye, the two men accused of leading a failed coup attempt against the president earlier this year. Current deputy police chief Godefroid Bizimana and newly appointed public security minister Alain Guillaume Bunyoni made the list from the government side. The sanctions block their assets and impose travel bans.

Watch the VICE News dispatch _Election Results and Post-Poll Violence: Burundi on the Brink_**: **

The US has also blocked property and interests held by the men in the US. The Treasury Department now has the power to impose similar orders against any Burundians accused of threatening the country's security, committing human rights abuses, or undermining democracy. Other sanctionable offenses include targeted violence against women and children, or the recruitment of underage soldiers.

Following the announcement, the US State Department highlighted offenses committed by both the government and its opponents. National Security Council spokesman Ned Price said the State Department has collected credible reports of targeted killings, arbitrary arrests, torture, and political repression by Burundi's security forces.

"Recent dangerous rhetoric by government officials has further contributed to the climate of fear and risks inciting further violence," he said.

Price also noted violence that Nkurunziza's opponents have been accused of carrying out against both government officials and civilians, specifically calling out the May 2015 coup orchestrated by Niyombare. Price said these actions have added to the current instability in Burundi.

"We call upon all parties in Burundi to reject violence, and we will continue to investigate and impose consequences against leaders from the government or opposition who resort to violence and obstruct a political resolution to this crisis," he said.

Burundian officials reported that five people were killed on Sunday, adding to the hundreds who have died since the unrest began earlier this year. There were also reports of shelling and clashes near Nkurunziza's office, according to Reuters. The news agency also quoted a military official saying mortars had been launched at the offices of state-run media outlets.

Watch the VICE News dispatch **_Fleeing to Rwanda: Burundi On The Brink:**_

There has also been a string of high-profile homicides in recent weeks. Earlier this month, Welly Nzitonda turned up dead in Bujumbura's Mutakura neighborhood. Nzitonda was the son of human rights activist Pierre Claver Mbonimpa. Mbonimpa's son-in-law was murdered in October and gunmen attempted to kill the activist himself back in August.

In September, unidentified gunmen clothed in military fatigues shot and killed at least four people while attempting to assassinate the army's chief of staff on the streets of the capital Bujumbura. Assassins killed an opposition party spokesman in the capital just days earlier. A high-ranking military officer was gunned down in August.

Nkurunziza ordered Burundi's police force to restore security in the country by December, and commanded citizens to give up their guns or face prosecution as "enemies of the nation."

Since the crisis began in April, more than 200,000 Burundians have fled to the neighboring states of Rwanda, Tanzania, and the Democratic Republic of the Congo. International agencies have already been forced to open up new camps in Tanzania to accommodate the influx of new refugees amid the current wave of violence.

The international community has raised concerns that the current crisis in Burundi could escalate into a larger conflict. On November 12, the United Nations Security Council voted unanimously on a resolution condemning the violence and human rights violations, while agreeing to deploy a team to look at options for handling security issues. The Security Council gave Secretary-General Ban Ki-moon 15 days to develop a course of action for UN presence in the country.