The Pakistani Government has never acknowledged detaining Siddiqui and made no statement on Tuesday about her arrest. However, its diplomats in the US have sought consular access to her while she is in US custody, officials said.

Pakistan’s civilian Government has said it wants to move ahead with resolving missing-persons cases such as Siddiqui’s. But the governing coalition, beset by infighting, has had a difficult time establishing any significant authority over Pakistan’s intelligence establishment.

Most of the missing are thought to be held under the auspices of the military or security agencies such as the ISI.

Siddiqui’s lawyer in Pakistan, Iqbal Jaffry, has been trying to force officials to disclose any information they have about the neuroscientist’s whereabouts over the last five years.

The Pakistani Supreme Court agreed earlier to hear Jaffry’s motion, aimed at compelling the Government to disclose what it knows about Siddiqui’s status after her disappearance.