Macedonia's government and opposition parties should agree on reforms that could open an invitation for the Balkan country to join NATO next year.
The United States "wants to see NATO invitations (for the region) issued in 2008," said Rosemary DiCarlo, deputy assistant secretary for European and Eurasian affairs.
But, she said "Macedonia will have to make continued progress" in political, economic and defense reforms.
"More work remains to be done, and time is short," DiCarlo said, after talks with Macedonian Prime Minister Nikola Gruevski.
DiCarlo also called for further implementation of the 2001 Ohrid peace agreement, which ended six months of clashes between government forces and ethnic Albanian separatists. She also urged stronger action against corruption and human trafficking.
Macedonia, Albania and Croatia, which have been working toward becoming a NATO member since 2002, are hoping to join the alliance in 2008.
DiCarlo also said the U.S. wants the status of neighboring Kosovo resolved "this spring."
"We do not believe that delaying the resolution of this issue will lead to greater stability of this region, nor necessarily improve the plan that is on the table," she said.
Kosovo has been administered by the United Nations since NATO airstrikes in 1999 ended a brutal Serbian crackdown on ethnic Albanian insurgents.
A U.N. plan that proposes internationally supervised independence for Kosovo has been rejected by Serbia, with strong support from Russia, a permanent member of the Security Council with veto power.