A roadside bomb exploded close to the convoy of Afghan Vice President Amrullah Saleh on Wednesday morning, his spokesman said.

"Today, once again the enemy of Afghanistan tried to harm Saleh, but they failed to get to their evil aim, and Saleh escaped the attack unharmed," Razwan Murad wrote on Facebook.

Saleh, who is the senior of Afghanistan's two vice presidents, was not harmed. However, a number of his security guards were wounded in the incident, according to Murad. The blast killed at least four people and wounded 16, a Health Ministry spokesman said.

Read more: Deutsche Welle