Over 21,000 primary and secondary education teachers have been on strike in the Angolan southwestern province of Huíla, since April 29, leaving more than 700,000 students sitting at home.

It is the first time, in more than a decade, that a union has been able to achieve such level of support and mobilization.

On April 30, the National Police detained two members of the National Teachers Union (Sindicato Nacional de Professores - SINPROF).

Paulo Simão and Albino Daniel were arrested when they were handing out leaflets informing the public on the teachers' strike, which had started the previous day. The province's teachers are demanding the improvement of their working conditions and the payment of overdue salaries and subsidies.

The detention of the two union leaders heightened the campaign of intimidation executed by the ruling MPLA party and led by the provincial governor, Marcelino Tyipinge.

Anti-riot police units had been deployed in several schools, harassing teachers not to join the strike, and union leaders kept receiving anonymous letters with veiled accusations and threats.

In his capacity as provincial governor, Marcelino Tyipinge issued a statement calling the strike illegal, arguing that the union's assembly did not have the quorum to make such a decision.

Meanwhile, in his capacity as the provincial head of MPLA, the same Marcelino Tyipinge signed another communiqué in which his party accused the union of being instigated by the opposition parties.

None of this is a novelty, in the context of Angola's culture of fear and intimidation against any action or people who may be considered a threat to the MPLA tight grip on all sectors of society. Last year, teachers were intimidated and arrested in Lunda-Norte and Bengo provinces for demanding better working conditions.

What is remarkable is that the Huíla teachers and their union leaders did not let themselves be intimidated. In a show of defiance and resistance, the teachers united and succeeded in bringing the education system in the province to a halt.

The union leaders denounced the anonymous letters sent to them and responded swiftly to the governor's claims of illegality.

They proved that they had their largest ever assembly, on April 20, including representatives of the province's 14 municipalities, and demonstrated that the governor, who had been formally invited to attend the meeting, did not care to respond or send a representative.

When Mr. Simão and Mr. Daniel were detained, hundreds of teachers gathered at the Municipal Headquarters of the National Police in Lubango, where their colleagues were being held.

The teachers were able to swiftly call an emergency meeting, using text messages, gathering more than 2,000 teachers in a school in Lubango on the day after the detentions took place.

The emergency assembly decided to call for a street protest to be held on Saturday in support of the colleagues who had been detained.

And yesterday, in a confusing summary trial held in Lubango, the two union leaders were release without charges. The flimsy accusations against them - disobedience and insult to the authorities - were only communicated to their lawyer minutes before the hearing, but, even so, could not hold.

The police officers clubbed Mr. Daniel on the head, while both union leaders did not resist arrest or argued with the authorities. In court, the police claimed that its officers had been assaulted, among other offenses.

With the growing anger in the streets, and the social networks buzzing with words of support for the teachers, the judge had no choice but to establish that there was no sufficient evidence of any criminal act and ordered the detainees to be released.

A high ranking police officer had confided to Maka Angola, after the arrests, that the National Police had been acting on the orders of governor Tyipinge.

He revealed that the governor had insisted in keeping the union leaders in prison to teach others a lesson, regardless of the law or the police willingness to release the detainees on the same day.

This is not a victory for the teachers. So far, the government has not conceded an inch or responded to any of their demands, except releasing the two SINPROF officers.

But surely the teachers in Huíla have taken a stand that will reverberate in the public sector, the largest employer in the country, for months to come.