Gambia's president has announced a ban on child and forced marriage and urged lawmakers to take up the issue quickly.

"As from today, child marriage below 18 years is illegal in the Gambia," President Yahya Jammeh said at a feast ending the Muslim holy month of Ramadan on Wednesday.

Jammeh said the decision to ban child and forced marriage must be tabled before the National Assembly. He expressed his resolve to fast-track the issue before the July 22 celebration that marks the anniversary of the military takeover that brought him to power in 1994.

The president warned that offenders will face heavy penalties over any reported child marriages, saying that "if you ... failed to report, if we know about it we will deal with you."