Problems deepened at Saudi conglomerate Saad Group late on Tuesday after credit agencies slashed ratings to default status or withdrew coverage altogether, saying Saad had ceased to pay creditors.

Saad said it had appointed specialist firm BDO Capital Finance to restructure its obligations and those at its Bahrain-based unit, Awal Bank.

"Both the Saad Group and Awal Bank are confident of a successful restructuring," Saad said in a statement.

Saad's woes have rattled a $30 billion empire built by billionaire Maan Al-Sanea and represent one of the biggest defaults to hit the Gulf Arab region since the onslaught of the financial crisis.

Privately-held Saad Group sent shockwaves through the Gulf on Monday, saying it plans to restructure the debt of its units hurt by a liquidity squeeze brought on by the financial crisis, as ratings agency Moody's cut its ratings on the group to junk status.

Moody's then withdrew its ratings altogether late on Tuesday, saying it lacked enough information about the group to continue.

Likewise, Standard & Poors on Tuesday cut its ratings to default status and then withdrew coverage due to a lack of information from management. Saad Group's accounts have been frozen by the Saudi central bank along with those of its chairman, Maan al-Sanea, Saudi bankers have told Reuters.

Standard & Poor's also said it believed accounts had been frozen. "We understand that Saad Group's action follows a regulatory freeze on certain personal bank accounts in Saudi Arabia of Saad Group's key owners," the agency said in a statement.

"The circumstances surrounding the regulatory freeze, including the motivation of the regulators, are not publicly known, although Standard & Poor's has confirmed both the freeze and the standstill agreement with Saad Group."

S&P's said Saad had entered into a standstill agreement with its creditors through which payments are suspended.

S&P's assigns a "D" rating when it believes that any default will be a general default and that the company will fail to pay all or substantially all of its obligations as they come due.-Reuters