Jordan has accepted a key demand of Islamic State (Isis) militants holding a Japanese journalist and Jordanian pilot by agreeing to release a prisoner in a proposed swap.

A government spokesman said Jordan had agreed to free Sajida al-Rishawi from death row if Jordanian pilot Muadh al-Kasasbeh – being held by Isis – is released.

There has been no word on whether Kenji Goto, a Japanese journalist who has appeared in videos released by the terrorist group, is involved in the proposed deal.

“Jordan is ready to release prisoner Sajida al-Rishawi if the Jordanian pilot Lieutenant Muath al-Kasaesbeh was released and his life spared,” Mohammad al-Momani, a government spokesman, was quoted on state television as saying. He did not make any reference to Goto.

On Tuesday, Isis militants said the hostages had 24 hours to live unless Rishawi was released.

Rishawi, 44, had been sentenced to death after being convicted for her part in an al-Qaida attack on a string of hotels in Amman in 2005 that killed 60 people.

Japan’s prime minister, Shinzo Abe, condemned as “despicable” the release of the video purporting to show Goto, accompanied by a warning that he and Kasasbeh had hours to live unless Rishawi was released.

Three days earlier Goto was heard in another audio clip announcing that his friend Haruna Yukawa, 42, had been beheaded after Isis’s 72-hour deadline for Japan to make a $200m payment expired.

The 1m 50s clip is accompanied by a photo of Goto holding what appears to be a Photoshopped image of Kasasbeh, whom Isis have been holding since his aircraft crashed during a US-led bombing raid over eastern Syria in late December.

The man in the clip says: “She [Rishawi] has been a prisoner for a decade and I’ve only been a prisoner for a few months. Her for me, a straight exchange.”

Abe said: “This was an extremely despicable act and we feel strong indignation. We strongly condemn that.

“While this is a tough situation, we remain unchanged in our stance of seeking help from the Jordanian government in securing the early release of Mr Goto.”