Washington expects strategic ally Romania to stick to its rule of law and IMF commitments in order to avoid a "replay" of the political crisis last summer, the US ambassador to Romania told AFP.

"Romania made these promises. Will it keep them after all? Keeping all of your promises can be a life and death question in an alliance," Mark Gitenstein said in an interview, just before ending his three-year mandate in Bucharest this week.

The United States has decided to deploy missile interceptors in Romania as part of a future defence shield to be operational in 2015, a move showing the strength of the ties between the two countries.

But a failed attempt by the ruling Social-Liberal Union (USL) this past summer to unseat centre-right President Traian Basescu earned Bucharest sharp rebukes from the US and the European Union, which Romania joined in 2007.

Concerned about pressure on the judiciary, both Washington and Brussels said the tactics of Prime Minister Victor Ponta's coalition had cast doubt on the former Communist country's democratic credentials.

US Secretary of State Hillary Clinton last week said that "challenges to constitutional processes in Romania" earlier this year were a "troubling development" in the EU.

Ponta has pledged that the rule of law will be respected and his coalition won a comfortable majority in parliamentary elections last Sunday.

He also said Romania will respect the terms of its financial agreement with the International Monetary Fund by privatizing state-owned enterprises and keeping fiscal discipline.

The current ruling coalition deserves credit for saying they will comply with the IMF conditions and the criteria set by the EU to improve the rule of law and the fight against corruption," Gitenstein said, adding: "They have to keep their promises."

"I see so far every indication that they are going to do that. But if they dont, it will be a big problem and they will face another crisis," he said.

-- Convincing investors, raising living standards --

"Don't have a replay of this summer" was his advice to Romanian politicians, warning it could hurt investments in the EU's second poorest member after Bulgaria.

"You have to convince investors that the rule of law is being complied with here, that there is transparency, that it is predictable," Gitenstein said.

"If they do do that, they will empower and help create a middle class."

Romania has seen four governments in four years and analysts warn of more turmoil if Basescu refuses to reappoint Ponta as prime minister despite the USL victory.

"This is not only about what investors want but it is about the standard of living for Romanians, it is about whether their kids decide to stay here or not," said Gitenstein whose Romanian grandparents settled in the US more than a hundred year ago.

About three million Romanians have emigrated looking for jobs and better living conditions elsewhere, raising fears of a "brain drain".

"The third language spoken at Microsoft's head office in Redmond is Romanian," Gitenstein said.

Meanwhile the average monthly wage in Romania remains as low as 350 euros (460 dollars).

The central European country has the largest number of working poor on the continent and the gap between rich and poor has widened.

"Romanians have to rein in that natural instinct of those in the elites to concentrate wealth and power," Gitenstein commented.

In a country where only 41 percent of the voters turned out to the polls last weekend, Gitenstein believes social networks will make a difference.

"Young Romanians don't see the political parties as the vehicle for change, but their own social networks," he said, noting that over one million young people engaged in a programme called Restart Romania to fight corruption and abuses through the IT.

However, the diplomat whose every appearance has been eagerly followed by Romanian media remains an optimist.

"In the US, a hundred years after our revolution, we were still dealing with the powerful moguls, who owned the railroads, political parties, the media --the Carnegies, the JP Morgans. . . and it was only in the 20th century that we began to break up these trusts," Gitenstein said.

"Romania as a young democracy is trying to do in two decades what it took us in the US a hundred year to do and they have made tremendous progress."