The cushion U.S. auto makers once had in markets outside of their struggling home country is shrinking fast as sales sink around the globe.

General Motors Corp. (GM) and Ford Motor Co. (F) reported steep sales declines last month in Europe, Brazil and Canada, with other regions expects to follow suit amid a deepening global economic slump.

European auto sales fell 18% in February, with only Germany boasting gains following government incentives for buyers scrapping old cars in favor of new.

GM, asking for billions aid from European governments, reported a 22% decline, while Ford said sales fell 14%.

Until recently, global auto sales have been a haven for Detroit's auto makers, faced with growing unemployment, a credit crunch and the housing crisis at home.

Global auto sales fell about 3% in 2008 and are expected to sink another 10% this year, according to forecasting firm IHS Global Insight.

Operations in emerging markets that had been immune to troubles in industrialized nations are showing signs of strain.

In Brazil, GM and Ford both reported sales declines in February from the previous month, while overall sales notched up a modest 1%. GM sold 35,757 cars and trucks last month compared with 38,201 in January, while Ford sold 22,461 cars and trucks in February, down slightly from 22,561 units in January.

Sales in Brazil have been helped by tax breaks for auto purchases that run until March 31. GM last week reported sales in Canada fell 57% from a year ago, hit by many of the same woes dragging down U.S. sales. Meantime, the auto maker plans to scale back production in Thailand, touching even GM's seemingly immune Asia Pacific unit.

A GM spokesman said Friday that the company will temporarily close a plant in Thailand this month to address excess inventory.

-By Sharon Terlep, Dow Jones Newswires; 248-204-5532; sharon.terlep@dowjones.com.