The embassy advised citizens to consider their personal safety during trips as the FG plans to close down the Nnamdi Azikwe airport for repairs.
In a circular issued by the US Embassy on Tuesday, 24 January 2016, American officials were also reminded of existing restrictions on trips to Kaduna, Kano and Port Harcourt.
This comes in response to recent announcements by the Federal Government regarding international air travel from the Federal Capital Territory, Abuja.
On January 5, the FG disclosed that the Nnamdi Azikiwe International Airport, Abuja would be closed from March 8 to April 19, 2017, to repair the runway.
During that period, local flights will be re-routed to the Kaduna airport while international airlines will suspend flights to Abuja in favour of the airports in Kano, Lagos and Port Harcourt.
The increase in air traffic at the Kaduna airport raises the possibility of attacks and the government recognises this.
There are reports of plans to increase police and military presence in and around the airport as well as the rail and road corridors linking Kaduna and Abuja.
Still, the US mission acknowledges the threats that exist in high-risk areas such as Port Harcourt as well as Kaduna, where religious violence is making daily headlines.
According to the circular, "U.S. officials and their families must receive advance clearance by the U.S. Mission for any travel to or from Kaduna, Kano, and Port Harcourt, including overland transit to airports outside Abuja".
This warning further casts doubts on the general state of security as well as the government's efforts to inspire confidence in the safety of lives and property within the country.
It also follows a trend of travel restrictions and warnings issued by the US embassy in recent times; the embassy's official site has a security warning advising citizens against travelling to 17 states, including Edo, Kebbi, Rivers and Yobe, due to the risk of armed robbery, attacks and kidnapping.