Bolivian President Evo Morales on Friday urged striking members of the armed forces to return to their barracks, calling for a return to military "discipline" by the soldiers.

Morales demanded that the troops end a strike that has lasted several days, calling their refusal to obey orders "a betrayal of the homeland."

"A military without discipline, ceases to be a military," Morales declared at an event marking the anniversary of an army military college.

"The people need you," Morales pleaded to the soldiers and low-ranking officers.

"The people place their trust in the sergeants. Officers and commanders, your president has placed his faith in you," he declared.

The striking non-commissioned officers, most of whom, like Morales, are of native origin, are protesting the lack of opportunities for advancement in the military, complaining that most of those promoted are white or of mixed-Indian and white heritage.

Bolivia sacked some 700 members of the military on Thursday in response to the strike.

The military acted after about 2,000 uniformed sergeants from all services protested through downtown La Paz.

The protest was set off by the sacking of 13 non-commissioned officers last week for refusing to obey orders and for mutiny.

But the strikers' grievances extend to treatment of the mainly Aymara and Quechua non-commissioned officers by higher-ups.

Among their demands were changes to rules that block non-commissioned officers from promotion beyond the rank of sergeant, or entry to training institutes.

"We are not against the government," said Johnny Gil, head of an association of non-commissioned officers.

"We are against this system, this capitalistic, neo-liberal, colonial model within the military."

The association has said the military should respect a new constitution promulgated by President Evo Morales, himself an Aymara and Bolivia's first president representing the country's indigenous majority.

The constitution guarantees racial and gender equality in the impoverished South American nation.

Bolivia's 38,000 strong armed forces have about 10,000 non-commissioned officers.

Analysts say that failure to address the grievances could translate into lost votes at the ballot box later this year, when Morales runs for a third term in office.

"If the government fails to meet these demands, it could lose electoral support ... of a large part of the Armed Forces distributed throughout the country," said Marcelo Silva, an analyst at the Nuestra Senora University in La Paz.

Samuel Montano, an expert in military affairs, told La Razon newspaper that NCOs were a key constituency within the army because "they drive the tanks, the trucks. They are always in contact with the troops."