King Mswati III is one of the world's last absolute monarchs
Security has been tightened in Swaziland, where authorities are investigating a failed bomb attack near one of King Mswati III's royal palaces.
Swazi investigators are conducting a joint probe with counterparts from neighbouring South Africa into last Saturday's attempted bombing.
Meanwhile, a government official acknowledged there had been previous attempted bomb attacks.
He said an opposition group had claimed responsibility for Saturday's attempt.
Two activists - one Swazi and one South African - were killed planting the device near the capital, Mbabane, while a South African survivor was detained.
Government spokesman Percy Simelane told the BBC's Focus on Africa programme that the opposition People's United Democratic Movement (Pudemo) had said it was behind the bombing.
'Failed to convince'
Authorities say they have found other bombs near railways, bridges and roads, but Mr Simelane played down the threat from Pudemo.
"They have a following but unfortunately for them, that following is not bigger than the number of people who are for the system," he said.
"It is simply because they have failed to convince the people that they want to kill the people, and we do not call that democracy."
Even so, authorities have increased police presence around government buildings in Mbabane over the last week, the BBC's Thulani Mtwethwa reports.
The attempted bombings come amid a rise in opposition to one of the world's last absolute monarchies.
The Swazi opposition says they are a result of people's frustrations with a ban on political parties.
Swaziland held its first parliamentary election under a new constitution a week ago.
On the day of the election, authorities blocked protesters who said they wanted to shut down the border crossing between landlocked Swaziland and South Africa.
South African unionists held protests on their side of the border in solidarity with Swazi activists.
Some Swazis blame King Mswati III for plunging the country into poverty and failing to tackle an Aids epidemic.
The king has been in power since 1986.
His government recently organised a lavish $12m (ú6.6m) party to celebrate the king's 40th birthday as well as the 40th anniversary of the country's independence from Britain.