The biggest-ever summit of NATO leaders will get underway today in the suitably imposing setting of Romania`s Parliament building. Security is tight. With the heads of the 26 member nations, partners and other international institutions in Bucharest, the authorities are taking no chances. NATO enlargement is on the agenda, along with the alliance`s role in Afghanistan, EuroNews report.

George W. Bush has arrived, fresh from his stopover in Kiev, for his farewell summit as US President. He is expected to push for Ukraine and Georgia to be allowed to begin the process of joining up.

But it may prove an uphill struggle. France and Germany, backed by several smaller countries, oppose the plan, fearing it could upset the balance of power with Russia.

NATO Secretary-General Jaap de Hoop Scheffer is in favour, however, and says Moscow has no right of veto. But Russia, whose leader Vladimir Putin will be a guest at the summit on Friday, has warned of a crisis in relations if Ukraine tries to join.

US officials have denied diplomatic talk of a possible trade-off, whereby Moscow would accept US plans for an anti-missile shield in central Europe against a delay in NATO membership for Kiev and Tbilisi.