Three policemen were wounded, he said.
There could have been civilian casualties as the explosion had occurred in a busy area, Barise said.
In another incident in south Mogadishu, one person died and three were wounded when a landmine targeting a police vehicle exploded and hit a bus instead, witnesses said.
"The police escaped unhurt. We were very fortunate we were not caught in the blast," Sheikh Salab, a local resident, said.
The attacks come soon after the killings of two prominent Somali journalists over the weekend and intensified assaults on Ethiopian-backed Somali troops by suspected fighters.
Mogadishu, one of the world's most violent cities, has been rocked by violence since January when the interim government and Ethiopian troops drove out the Union of Islamic Courts, which had ruled much of southern Somalia for six months last year.