A Nigerian student who was arrested last year for alleged drug trafficking in Saudi Arabia has been freed, the Nigerian government says.

Zainab Aliyu was accused of smuggling 2,000 packs of a strong pain killer.

The Nigerian authorities later found that the drugs had been planted in her luggage by a criminal gang.

Drug trafficking is a capital offense in Saudi Arabia, which practices conservative Islam. Those found guilty are executed.

This was the fate earlier this month of a Nigerian woman, who was beheaded in the city of Mecca, along with two Pakistani men and a Yemeni man.

Ms. Aliyu's detention sparked protests and with supporters in Nigeria using the hashtag #FreeZeinab to call for her release.

Her freedom comes as hundreds of her fellow students gathered at Maitama Sule University in the northern city of Kano on Tuesday to demand her release.

On Monday, President Muhammadu Buhari ordered the attorney general to intervene in the matter.

His aide tweeted the news of Ms. Aliyu's release using the popular hashtag #FreeZeinab.

Ms. Aliyu was arrested at her hotel in Medina by Saudi police last December, shortly after arriving for the lesser hajj with her family - and remained in detention until Tuesday.

The Saudi authorities had accused her of trafficking 2,000 packs of Tramadol in a bag tagged with her name that had been left at the airport.

Recently, the National Drug Law Enforcement Agency of Nigeria (NDLEA) said it had uncovered a criminal gang that had been planting illicit drugs in travellers' luggage.

An investigation was launched after Ms. Aliyu's father reported the case to the police and it led to the arrest of six officials at Mallam Aminu Kano International Airport.

They have been accused at a federal high court of framing Ms. Aliyu and have not commented on the charges.