Police in Senegal have arrested the son of former President Abdoulaye Wade on suspicion of corruption.

Karim Wade is suspected of illegally amassing about $1.4bn during his father's rule, his lawyers said.

Karim was a senior minister during his father's rule from 2000 to 2012, and was in charge of major infrastructure and energy projects.

Investigators had set him a deadline of Monday to prove his innocence, after accusing him of corruption a month ago.

He is among five former ministers whom prosecutors said they would investigate last year.

In March 2012, Macky Sall won the presidency from Abdoulaye Wade and pledged to fight corruption.