Mario Masuko was acquitted of treason charges in 2002
A leading Swazi democracy campaigner has been charged under a new anti-terror law for allegedly supporting a series of recent bombings.
Mario Masuko, who leads the People's United Democratic Movement (Pudemo), was detained after police raided his home on Saturday.
He became the first person to be arrested under an anti-terrorism law introduced in September.
Swaziland is one of the world's last absolute monarchies.
Mr Masuko's son had said earlier that his father was being held for alleged possession of weapons-making materials.
He said he did not believe there were any such materials at his father's home.
But in a preliminary court hearing in Siteki on Monday, there was no mention of that accusation, the BBC's Thulani Mthethwa reports.
He says Mr Masuko was simply read the charge - that he had made statements suggesting that attempted bombings against government structures should continue.
With the case expected to go to the high court for trial, Mr Masuko did not enter a plea.
If convicted, he could face up to 25 years in prison.
There was tight security at the courtroom for Monday's hearing, our reporter says.
Swaziland held its first elections under a new constitution in September, but political parties were not allowed to participate.
Following the poll, authorities said they had discovered a number of bomb plots, including one failed attack near one of King Mswati III's royal palaces.
They banned Pudemo and three other groups under the anti-terrorism act on Friday.
King Mswati III is one of the world's last absolute monarchs
Swazi Attorney-General Majahenkhaba Dlamini said the groups targeted under the new law were "associated with terrorist acts".
He said he could not talk further about the evidence, but denied the law was being used to silence critics.
"The idea is not to punish eminent political opponents, it is to punish entities and persons involved in terrorist acts," he told the BBC's Network Africa programme.
Mr Masuko has been campaigning for multi-party politics for many years.
He was acquitted on treason charges in 2002, after allegedly calling for the overthrow of the monarchy.
"We will let the court deal with this matter and see what the government has to put against my father," his son said.
King Mswati has been in power since 1986.
Though he remains popular with many Swazis, opposition from pro-democracy groups has been growing.
Critics point to the king's lavish lifestyle in a country where most live in poverty, and have accused him of failing to tackle an Aids epidemic.
Mr Masuko dismissed the recent elections as a "window-dressing exercise trying to pull wool over the eyes of the international community".