A blast on a Tel Aviv bus on Wednesday injured at least 10 people, three of them seriously, in what was "a terrorist attack," the prime minister's spokesman and medics said.

"A bomb exploded on a bus in central Tel Aviv. This was a terrorist attack. Most of the injured suffered only mild injuries," Prime Minister Benjamin Netanyahu's spokesman Ofir Gendelman said on his official Twitter account.

Medics said at least 10 people were wounded, three seriously.