Hundreds of people, including a presidential candidate, have launched a mass hunger strike to protest against the detention of demonstrators earlier this month.

Activists at a rally outside Cairo's press syndicate on Sunday said they would refuse food in solidarity with the estimated 400 people who were arrested by the military during protests in the Abbaseya area of Cairo in early May.

The protests were held to protest against military rule and Article 28 of the Constitutional Declaration that makes it illegal for decisions by the electoral committee to be challenged in court.

Many activists have said they will boycott this week’s elections. They feel the vote will not be free and fair as long as the country’s military rulers hold power.

Human rights lawyer Khaled Ali, the youngest presidential candidate, was among the hunger strikers.

“I’m here to say I want to say to Supreme Council of the Armed Forces [SCAF] that [they are] the Supreme Council of the counter-revolution,” Ali told Al Jazeera.

“They’re trying to defame the revolutionaries and destroy the revolution.”

Ali, who wore a sticker reading "Down with military rule” on his suit jacket, said detainees were facing torture. He described the detained protesters as some of the “best Egyptians”.

“They have to face military trials even though they are civilians. I’m here to demand their release,” Ali said.

One of the protesters on hunger strike, Um Ali, said she was there “in solidarity with the hostages of military dictatorship”.

“We can’t have elections when revolutionaries are in prison,” Ali said.

“Had there not been Article 28, by which you can’t appeal then maybe I would’ve voted. I’m going to spoil my vote.”

Another woman, Shams Haikel, told Al Jazeera: “I’m here in solidarity with the Abbaseya detainees and all other detainees.”

“I saw people who’ve been detained in very bad conditions,” she added.

Haikel said she is not going to boycott the elections, but that she will only vote for a secular supporter of the revolution.

“I’m not going to vote for an Islamist, we’re already an Islamic country,” she said, adding that her vote will likely go to either Abdel Moneim Aboul Fotouh or Hamdeen Sabahi.

During the protest at the press syndicate, Ali removed a small piece of paper from his pocket. On it was written: “bread, freedom, social justice”.

“This is for SCAF to know that revolutionaries will not give up their demands,” he said.

“[The detainees] are saying, ‘Go ahead and arrest us, we’re still going to get our freedom from you and any other dictator.’”

More than 11,000 people have faced military trial since protests began that ousted former president Hosni Mubarak.

Activists said that some of the hundreds arrested in the May protests began an open-ended hunger strike on Sunday.