Anwar Tarawneh (2nd R), the wife of Islamic State captive Jordanian pilot Lieutenant Muath al-Kasaesbeh, and his sister (R) weep after listening to a statement released by Islamic State in front of the Royal Palace in Amman January 28, 2015. [Photo/Agencies]

AMMAN/TOKYO - Jordan said on Thursday it was still holding an Iraqi would-be suicide bomber as a deadline passed for her release set by Islamic State militants who threatened to kill a Jordanian pilot unless she was handed over by sunset.

An audio message purportedly from a Japanese journalist also captured by the insurgents said the pilot would be killed unless Jordan freed Sajida al-Rishawi, who is on death row for her role in a 2005 suicide bomb attack that killed 60 people in Amman.

The message postponed a previous deadline set on Tuesday in which the journalist, Kenji Goto, said he would be killed within 24 hours if Rishawi was not freed.

In the latest audio recording purportedly of Goto, he said that Kasaesbeh would be killed "immediately" if al-Rishawi was not at the Turkish border by sunset on Thursday, Iraq time, ready to be exchanged for the Japanese hostage.

About an hour before the new deadline was due to pass, government spokesman Mohammad al-Momani said Jordan was still holding Rishawi.

"We want proof ... that the pilot is alive so that we can proceed with what we said yesterday -- exchanging the prisoner with our pilot," Momani told Reuters.

The pilot, Muath al-Kasaesbeh, was captured after his jet crashed in northeastern Syria in December during a bombing mission against Islamic State, which has seized large tracts of Syria and Iraq.

"We have not received any evidence that Kasaesbeh is alive. This is what we asked and have not received any proof," Momani said.

He said separately that Jordan was coordinating with Japanese authorities in an effort to secure the release of Goto, a veteran war reporter also being held by the radical Islamists.