The global police agency Interpol says India has not shared any information with it about last month's deadly attacks in Mumbai (Bombay).
Interpol secretary general Ronald Noble, who is in Islamabad, said its only knowledge of what happened had come from the media.
Pakistan also says it has had no firm information from Delhi.
India says Pakistani militants carried out the attacks, which left more than 170 people dead.
The information Interpol has about what happened in Mumbai is the same information that you have
Only one of the 10 gunmen, Mohammed Ajmal Amir Qasab, survived and he is in Indian custody.
On Monday India handed a letter to Pakistan it says was written by Mr Qasab, confirming he is Pakistani and asking for Islamabad's help.
The attacks have severely strained relations between the two countries.
Police in Indian-administered Kashmir said on Tuesday they had arrested three militants from Pakistan who were planning to launch suicide bomb attacks in the city of Jammu.
According to the police, one of those detained was a Pakistani army soldier and all were members of the Jaish-e-Mohammed militant group, which is violently opposed to India's presence in Kashmir.
There was no immediate response from the Pakistani army to the Indian allegation.
Mr Noble has been in Islamabad for talks with Rehman Malik, the adviser to the prime minister on interior affairs.
At the weekend he had met India's Minister of Home Affairs Palaniappan Chidambaram in Delhi.
Ronald Noble is heading an Interpol team to India and Pakistan
Mr Noble said in the Pakistani capital: "To date, India's government has not authorised India's police agencies to enter any data relating to the recent terrorist attacks in Mumbai into Interpol's databases.
"The information Interpol has about what happened in Mumbai is the same information that you have - it's information that was read in journals, that was read on the internet or that was seen on TV."
Mr Noble has said Interpol is willing to pass on DNA profiles, photos and fingerprints of the suspects worldwide.
He said it was Delhi's "sovereign choice" on whether to pass on evidence, but was confident more would be forthcoming.
"We are hopeful that it will happen very quickly. We've deployed a team there for that reason."
Mr Malik reiterated Pakistan's line that it is willing to take part in an investigation but has had no data from India.
"We want to bring the culprits to justice... We are prepared to co-operate with India but they have to bring us evidence."
India says militants of the Lashkar-e-Taiba group carried out the attack, citing evidence provided by Mr Qasab.
Mumbai police have listed in full the names and apparent aliases of the men it said carried out the attack, along with photographs, and says all were from Pakistan.
India's foreign ministry said Mr Qasab's letter to the Pakistan High Commission "stated that he and the other terrorists killed in the attack were from Pakistan and [he] has sought a meeting with the Pakistan High Commission".
Islamabad says it is examining the letter but has made no official response.
'Regrettable'
Meanwhile, the chairman of the US Joint Chiefs of Staff, Adm Mike Mullen, has urged Pakistan to work with India to combat extremism, a US embassy statement has said.
Pakistan has yet to respond to Mr Qasab's letter
Adm Mullen has been in Islamabad to meet the Pakistani army chief and head of the intelligence service.
The embassy said Adm Mullen urged Pakistan to "use this tragic event as an opportunity to forge more productive ties with India and to seek ways in which both nations can combat the common threat of extremism together".
Separately, Mr Chidambaram said comments by a minister that suggested there was another agenda to the killing of senior policemen in the Mumbai attacks were "wrong and deeply regrettable".
Minority Affairs Minister AR Antulay had questioned who sent anti-terrorism chief Hemant Karkare - who had been investigating suspected Hindu radical attacks - and others to their deaths at the scene of the attacks.
Mr Antulay said Mr Chidambaram had "clarified all doubts" and "the matter is settled".
BBC NEWS | World | South Asia | Interpol 'not given Mumbai data'
