The US President Barack Obama has bypassed the Senate to name six new appointees during the recess.
Those named included four new US ambassadors - to Azerbaijan, the Czech Republic, Syria and Turkey - as well as a deputy attorney general.
Recess appointments are made when the Senate is not in session and last until the end of Congress's next session.
Nominations for many of those selected had been blocked for months by lawmakers.
Mr Obama named Robert Ford as the new ambassador to Syria, an appointment process that he began in February.
Senators had stalled on nominating an ambassador, arguing it would reward the country for good behaviour.
The BBC's Iain Mackenzie in Washington says the White House has long argued that re-engaging with Syria is the best way of tackling extremist groups and ensuring its involvement is the search for peace in the Middle East.
The last American ambassador was withdrawn in 2005 after Syria was implicated in the assassination of the Lebanese Prime Minister Rafiq Hariri.
Another of the Obama recess appointments is James Cole, to the position of deputy attorney general to the justice department.
Republicans had expressed concerns about his links to American International Group, where he was an independent consultant until its near collapse and government bailout in 2008.
The other ambassador appointments are Matthew Bryza (Azerbaijan); Norman Eisen (Czech Republic) and Francis Ricciardone (Turkey).
Some senators had opposed confirmations for a variety of reasons.
The recess appointment system has been regularly used by both Democratic and Republican presidents, our correspondent says.