Hundreds of thousands of federal workers were unable to report for work on Monday, as the US Senate struggles to end a government shutdown.
Some will not be paid until the stalemate is resolved.
A rare Sunday session of the Senate yielded no agreement between Democrats and Republicans, with immigration one of the main sticking points.
The US Embassy in Armenia said in a Facebook post that scheduled passport and visa services will continue during the lapse in Congressional appropriations as the situation permits.
It added, however, that the Facebook page will not be regularly updated until full US Government operations resume, with the exception of emergency safety and security information.
At midnight on Friday, lawmakers failed to agree on a spending bill. The bill was not a plan for funding for the whole of 2018, but would have kept things running until the middle of next month.
Democrats refused to back a temporary deal until their concerns on immigration reform were dealt with.
Under Senate rules, the bill needs 60 votes in the 100-member chamber.
The Republicans currently have 51 senators, so they need some Democratic support to pass a budget.