Headley`s case involves a trial in the US and Pakistan has not been given access to him, Foreign Office spokesperson Tehmina Janjua told a weekly news briefing.
She was responding to a question about Headley`s testimony linking Pakistan`s ISI to the Mumbai attacks.
Pakistan is "not in a position to determine the details of what he (Headley) is saying or what he is not saying", Janjua said.
"Therefore, what we can say is that it is our expectation that all sides will refrain from vitiating the atmosphere by baseless speculation" from the trial, she said.
Headley`s testimony in a Chicago court, which is conducting the trial of his friend Rana, has detailed the alleged role of some ISI officers and Lashker-e-Taiba commanders in planning and executing the Mumbai attacks.
The son of a Pakistani broadcaster and an American woman, Headley struck a plea bargain with US authorities to testify against other suspects in order to avoid the death penalty.
In response to another question, Janjua said Pakistan had given India a non-paper on the Siachen issue during a recent meeting of the Defence Secretaries of the two countries in New Delhi.
The non-paper ? diplomatic parlance for a negotiating text informally circulated to facilitate discussions without making any commitment to the contents ? states Pakistan`s position that was clearly outlined in the past.
"It is basically putting down on paper clearly our position with regard to Siachen...It`s our clear position so that there is no ambiguity," Janjua said.
Janjua evaded a question on remarks by Indian leaders about the danger of terrorism emanating from Pakistan, saying "Pakistan does not intend to run any of our relationships through the media. Any effort to run a relationship through the media does not lead to constructive engagement."
Pakistan has gone into the dialogue process with India that resumed earlier this year with an "open and constructive mind and with the objective of having result-oriented talks", she said.
The two countries are in the process of finalising dates for talks between their Foreign Secretaries on the issues of peace and security, Jammu and Kashmir and friendly exchanges, she said.
"Our dialogue process with India is going according to schedule," she added.