The Yemeni Security authorities Sunday granted a conditional release for a girl suspected of being behind mailing two alleged parcel bombs through cargo planes bound for the United States, a security official told Xinhua.

The release came a day after her arrest by the Yemeni security authorities following a tip-off from the U.S. intelligence.

"Hanan al-Samawi was set free on Sunday evening on condition that being available when she was summoned for regular investigation," the official of the intelligence told Xinhua on condition of anonymity.

"Americans and Saudis haven't provided enough evidences that lawfully convict the Yemeni girl," the official said, adding that "nothing was proved against her."

"So far, the girl is clear," he said.

Hanan al-Samawi, a 22-year-old Yemeni female student at her final year of the computer science degree in Engineering Faculty of the Sanaa University, was arrested Saturday in the capital Sanaa by forces of the National Security Agency (intelligence) following a tip-off from the U.S. intelligence agencies, according to state media.

On Saturday, Yemeni President Ali Abdullah Saleh said in a press conference that the security forces surrounded a house of a girl allegedly behind the mail bombs.

"According to a tip-off we received, she is a girl who had dispatched the two parcels through those cargo agencies," Saleh told reporters.

The failed terror plot, in which two suspicious packages were found Thursday night on cargo planes originated from Yemen and destined for the United States, has spurred security scare across the Atlantic.

With an intelligence help by the United States, Yemen has beefed up security campaign including air raids on al-Qaida wing since the terrorist group claimed credit for a failed attempt to blow up a U.S. passenger plane in December 2009.