Nato has confirmed it will not yet offer membership to Georgia or Ukraine after the 26-member alliance was split amid strong objections from Russia.
Moscow said Nato's promise at a summit in Romania that the nations would join one day was a "huge strategic mistake".
Macedonia vowed to leave the summit after it was denied entry. Albania and Croatia were given the green light.
Nato members were set to endorse US plans for anti-missile defences in Europe, which Russia has opposed.
US and Czech officials have agreed to base a missile defence radar on Czech soil.
This issue is something of a success for US diplomacy, says the BBC's Jonathan Marcus from the summit.
However, the US had also called for Georgia, Ukraine and Macedonia to be allowed to join, so the decision to postpone their membership process was a setback for President George W Bush, our correspondent adds.
A night of diplomatic wrangling over the new members had poisoned the summit's atmosphere, he says.
The alliance decided not to offer Ukraine and Georgia a membership action plan - a gateway to membership - but agreed on Thursday to review this in December.
NEW NATO MEMBERS
Pop: 3.6 million
Area: 28,748 sq km
Miltary service: compulsory but due to be abolished by 2010
Army: aiming for army of 14,500
Pop: 4.4 million
Area: 56,538 sq km
Military service: draft abolished in 2008
Army: aiming for army of 16,000
Nato Secretary General Jaap de Hoop Scheffer told a news conference that Georgia and Ukraine would become members eventually.
Germany and France had been opposed to putting the two nations on the path to membership, amid concerns voiced by Russia over Nato's eastward expansion.
"Georgia's and Ukraine's membership in the alliance is a huge strategic mistake which would have most serious consequences for pan-European security," Interfax news agency quoted Russia's Deputy Foreign Minister Alexander Grushko as saying on the sidelines of the summit.
Georgian diplomats said they were "not happy" with the delay but welcomed the promise of eventual membership.
Macedonian officials said their rejection was a "huge disappointment" that would undermine stability in the Balkans, and said they would leave the three-day summit early.
Macedonia's membership was strongly opposed by Greece, which has a northern province that is also called Macedonia.
It argued that the former Yugoslav republic's insistence on being known as Macedonia implied a territorial claim.
Separately, President Nicolas Sarkozy indicated France would return next year to the Nato military command it left in 1966 in protest at the dominance of US commanders.
He also said a battalion of extra French troops would be deployed to Afghanistan, easing fears of a crisis within the Western coalition there.
The US says the French move, expected to involve up to 1,000 extra soldiers, will free up some of its troops to move to southern Afghanistan, where Canada had demanded Nato reinforcements be sent.
Canada's parliament voted last month to extend its military mission in volatile southern Afghanistan to 2011 - but only if its allies sent reinforcements.