Spain's Foreign Ministry says a bomb has exploded at the country's embassy in the Libyan capital, Tripoli, damaging an outer wall but causing no injuries.

A spokeswoman said on Tuesday that the ministry was not aware of any group having claimed responsibility for the blast.

She says some security personnel were inside at the time of the explosion late on Monday. She spoke on condition of anonymity under ministry regulations.

Spain evacuated most embassy staff from Libya last July because of the worsening security situation in the North African country.