By Carla Mozee

Mexican and Brazilian equities turned lower Wednesday, tracking a pullback on Wall Street where ongoing weakness in the U.S. housing sector and a downgrade of Portugal's credit rating rekindled global growth worries.

Brazil's Bovespa fell 0.7% to 69,926 as utilities, finance and communications stocks traded in the red. But losses on the blue-chip index were limited by gains among market heavyweights state-run oil giant Petrobras (PBR) and iron ore provider Vale (RIO).

Mexico's IPC index fell 0.4% to 33,226 after having been up about by the same amount earlier in the session. Retail, mining and home-building stocks posted declines as advances among consumer discretionary, finance and industrial issues, including Empresas ICA (ICA), helped keep in the index on track for its seventh win in a row. The index has hit all-time highs in the past two sessions.

Empresas shares of rose 1.1% after the engineering and construction giant said it won contracts for two low-sulfur gas projects from Mexican state-run oil firm Pemex. The contracts are valued at $622 million, and the projects are part of Pemex's clean fuels program, the company said. ICA Fluor, the company's joint venture with Fluor Corp. (FLR), will book its $311 million portion of the award in the first quarter of this year.

Also, shares of America Movil (AMX) slipped 0.3% in Mexico City. The region's largest wireless services provider on Tuesday raised $4 billion through the sale of debt.

On Wall Street, the Dow Jones Industrial Average (DJI) fell 43 points to 10,846 and the S&P 500 Index (SPX) fell 0.4% to 1,169, giving up earlier gains following a downgrade of Portugal's long-term credit rating by Fitch Ratings to AA- from AA.

European equity markets also fell following the downgrade decision by Fitch, which cited "significant budgetary underperformance in 2009," as a key reason for the move. Earlier this month, Moody's Investors Service warned that debt and deposit ratings of Portuguese banks are at risk from a potential downgrade.

The downgrade of Portugal arrived amid lingering uncertainty over aid efforts for debt-strapped Greece by the European Union.

Meanwhile, the U.S. Commerce Department said demand for U.S.-made durable goods rose for a third consecutive month, up a seasonally adjusted 0.5% to $178.1 billion in February.

But monthly housing figures from the department were much less upbeat, as sales of new homes fell for the fourth straight month. Sales dropped 2.2% to a seasonally adjusted annual rate of 308,000 in February, the lowest rate since the government began recording the data in 1963.

"The recent bout of worry on the housing market does not appear to be going away," wrote Jennifer Lee, senior economist at BMO Capital Markets, in a clients' note.

Lee also highlighted that the government's homebuyer tax credit "does end in a little over a month...then that's it for government incentives."

Contracts must be entered by April 30, and closed before July 1, she wrote.