Mexican authorities say the number of mainly Central American migrants who were detained in April has risen by 79% in comparison to the same month last year.

Figures released by the Interior Department on Thursday show that 20,564 migrants were detained last month, compared to 11,486 in 2018.

Of those detained, 14,970 were deported.

Overall, detentions in the first four months of 2019 were 17% above the same period last year.

But even at that rate, Mexico appears to detain less than one-fifth of the migrants who are crossing the country to reach the U.S. border.

The department said there had been "a very notable increase" in the number of Central Americans, mainly Hondurans, entering Mexico this year.

Detentions in January and February of 2019 had been below 2018 levels.