MADRID (AP) -- Thousands of people marched in Madrid on Sunday to protest plans to privatize parts of their public health care system, with some questioning the motives behind the government's actions.

The march by employees and users of the system is the year's second large "white tide" demonstration, named after the color of the medical scrubs many protesters wear. Several similar marches took place last year.

Demonstrators thronged main boulevards in the center of the Spanish capital, carrying banners saying, "Public health care should be defended, not sold off."

The Madrid region has proposed selling the management of six of 20 large public hospitals in its jurisdiction and 10 percent of its 268 public health centers. It says these reforms are needed to secure health services during Spain's economic crisis.

But protesters were skeptical.

"This measure is politically inspired and not financial," said mechanical engineer Mario Sola, 47. "If public hospitals were unsustainably loss-making as we're being told, private enterprise wouldn't be interested."

Health care and education are administered by Spain's 17 semi-autonomous regions rather than by the central government.

Many regions are struggling financially as Spain's economy has shrunk due to a double-dip recession following the 2008 implosion of the once-prosperous real estate and construction sectors.

Some regions overspent during boom years, but are now excluded from borrowing on the financial markets to repay their accumulated debts, forcing them to seek savings and even request rescue aid from the central government.

Regional health councilor Javier Fernandez-Lasquetty called the protests irresponsible and said that "everyone has their point of view, but we are all fighting to defend the same thing."

Jose Gabriel Gonzalez Martin, president of Spain's Independent Civil Service Trade Union Center, said many people's suspicions were aroused when former government health officials acquired jobs with private companies lining up to take over medical analysis functions.

"It might be purely coincidental, but some coincidences are surprising," Gonzalez said.

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