The attacks were a shock to many in Hargeisa after years of peace
At least 29 people have died in a wave of coordinated car-bombings across northern Somalia.
Most of the casualties were in the Somaliland capital, Hargeisa, where the presidential palace, Ethiopian consulate and UN offices were targeted.
Two suicide attackers also killed six intelligence agents in their offices in neighbouring Puntland, the region's president says.
These are the first suicide attacks in the two relatively stable regions.
Somaliland has declared independence from war-torn southern Somalia but this has not been internationally recognised.
The region is a US ally in the fight against Islamist militants in Somalia.
Puntland's President Mohamoud Musa Hirsi Adde said that the attacks in both regions were coordinated, reports the AFP news agency.
"The whole plan was organised from the same place and by the same people," he said.
Somaliland President Dahir Riyale Kahin says the government is ready to defend the country.
The BBC's Jamal Abdi in Hargeisa says he saw body parts flying through the air after the attack on the Ethiopian consulate.
One of the buildings in the consulate was levelled to the ground and eight people were killed.
Our correspondent says the explosions shook surrounding buildings violently and there was gunfire after the last explosion.
He says the attacks came as a real shock to many people after years of peace.
Guards outside Somaliland's presidential palace opened fire on the attackers blocking them from entering the compound.
One car managed to get into the heavily fortified UNDP office complex before the explosives were detonated.
Eyewitnesses at the UNDP office said the attackers parked the car next to one of the buildings, which suffered the worst damage and heaviest casualties.
There is a lot of anxiety around the city and cars have been blocked from approaching the three locations.
There is no information about who was responsible for the three attacks, which took place within seven minutes of each other.
But some suspect Islamist insurgents, given the coordinated nature of the bombings and the targeting of Ethiopia.
The al-Shabaab group, which the US describes as a terrorist organisation, refuses to join peace talks until Ethiopian troops agree to leave Somalia.
Most of the casualties were in the Somaliland capital, Hargeisa
Ethiopia helped forces of the interim government oust Islamists from the capital, Mogadishu, in 2006 - since when Islamists have staged regular attacks in the city.
The bombings come as regional leaders meet in the Kenyan capital Nairobi, to discuss the ongoing crisis in Somalia and the performance of the transitional federal government.
On Tuesday, Ethiopian Foreign Minister Seyoum Mesfin made a rare criticism of the Somali government.
"Somalia's problems are not security but political," Mr Seyoum said, blaming disputes between the country's leaders for the prolonged crisis.
The transitional federal charter, which was adopted in 2004, expires next year when a constitution is supposed to be drafted and elections held.