Moody's financial ratings service announced Thursday that it has downgraded the ratings for seven government-owned firms in the United Arab Emirates, including investment company Mubadala.

Moody's said its rating for Abu Dhabi-owned Mubadala, which manages a portfolio of billions of dollars of investments in energy, industry, health, infrastructure and real estate, had been downgraded from Aaa2 to Aaa3.

Moody's also downgraded the ratings for Abu Dhabi-owned International Petroleum Investment Company (IPIC) from Aa2 to Aa3 and the Tourism Development and Investment Company (TDIC) from Aa2 to A1.

Explaining the three downgrades, it said "Moody's has decided to introduce a moderate distinction between their ratings and that of the sovereign" as there is no "explicit formal agreement" that the government will support them.

A senior official in Abu Dhabi's finance ministry slammed the decision.

"We obviously disagree with the reasoning involved in a number of Moody's decisions, especially those concerning TDIC, Mubadala, and IPIC," ministry undersecretary Hamad al-Suwaidi said in a statement.

Suwaidi said there had been no change in any aspect of government support for those three companies.

"Not only does the government back these entities, as Moody's correctly pointed out, fully and unconditionally, (but) we have a strong fiscal position and reserves that give us all the capacity we need to meet our commitments to these companies from our own resources."

Moody's also downgraded on Thursday the Abu Dhabi National Energy Co, lowered from Aa2 to A3, and Dolphin Energy, which transports gas from Qatar to the UAE and was downgraded from Aa3 to A1.

"The government level of support factored into (the Abu Dhabi National Energy Co)'s ratings was lowered" due to the company's "increasing commercial orientation" and "lack of ongoing and regular" government funding, Moody's said.

Dolphin's downgrade, meanwhile, reflected the "company's commercial... business activities."

And UAE national telecommunications company Etisalat's rating was lowered from Aa2 to Aa3, as support from the federal government factored into its rating was reduced from "high to medium," it said.

The outlook for those companies is stable, Moody's said.

The ratings agency also decreased the rating for giant Abu Dhabi real estate firm AlDar Properties from Baa2 to Ba1 (negative), due to "medium-term risks affecting its stand-alone profile inherent with the real estate sector."

Moody's had downgraded the ratings of six companies owned by the Dubai government in the wake of the emirate's November 25 announcement that it was seeking a six-month debt freeze for its Dubai World conglomerate.

Dubai's total debt is estimated at between 80 and 100 billion dollars, but some experts say it could be as high as 170 billion dollars.

Abu Dhabi came to Dubai's rescue with a 10-billion-dollar loan, preventing Dubai World subsidiary Nakheel from defaulting on 4.1 billion dollars in debt that came due in mid-December.

The UAE is a federation of seven emirates led by oil-rich Abu Dhabi.