Iraq has said it will show no leniency to the kidnappers of an Israeli-Russian researcher who has been missing for more than six months, as international pressure mounts on Baghdad to move forward with the investigation.
Elizabeth Tsurkov, a PhD student at Princeton University in the US, who was conducting research in Baghdad when she was kidnapped, was last seen leaving a coffee shop in the Iraqi capital in March.
The Israeli government believes she is being held by Kataib Hezbollah, an Iran-backed Iraqi armed militia.
Iraqi Prime Minister Mohammed Shia Al Sudani said from New York that authorities were still investigating.
"Our security forces are responsible for ensuring security for all those arriving in Iraq, including the woman who entered Iraq with a Russian passport and disappeared months ago,” Mr Al Sudani told CNN, referring to Ms Tsurkov.
“We are following the case, we are serious about revealing her fate and we will not be lenient," he said, without giving out further details.
Ahead of his trip to the US city, he told The New York Times “our information has not yet identified any particular group”.
“The incident damages the reputation of Iraq’s stability and the capability of our security agencies,” he added.
Last week, Ms Tsurkov's sister Emma said more must be done by the international community to ensure her safe return home.
"The US government needs to apply pressure to the Iraqi government to do everything they can to free my sister, because currently that's not happening," she told US channel PBS.
"It seems that, so far, everyone is passing the buck. Everyone wants to know what's happening, but no one wants to take the lead and take the responsibility of doing everything possible to bring my sister back."
Ms Tsurkov is "a Jewish woman at the hands of an extremist terrorist organisation. So, she is a completely innocent woman, a brilliant scholar, and a very kind person. She has done nothing wrong to anyone," her sister added.
Kataib Hezbollah, also known as the Brigades of the Party of God, is a powerful Iraqi Shiite militia that receives financial and military support from Iran.
The US designated the group a terrorist organisation in 2009.
In July, Kataib Hezbollah denied it was holding Ms Tsurkov and said her disappearance was a “dangerous matter that must be taken seriously”.
“Security officials and the army must stand together and work hard at uncovering the perpetrators and holding them to account,” the paramilitary group said.
“We will, as Kataib Hezbollah, spare no efforts to find the Israeli hostage in Iraq. We will find out who is behind these acts, how they are operating inside the country and who is aiding them."