An Indian policeman patrols outside the Mumbai High Court in Mumbai, India. (Rafiq Maqbool/AP)

ISLAMABAD, Pakistan — Even as Indian and Pakistani officials make high-profile efforts to repair relations, the nuclear-armed neighbors remain sharply at odds over the fate of seven Pakistanis accused of having a role in the 2008 terrorist attacks in Mumbai.

The suspects have been held in Pakistani jails since their arrest two years ago, and all are members of the Islamist militant group once known as Lashkar-i-Taiba. No formal charges have been filed, and no trial date has been set.

Most observers here say the slow pace of prosecution reflects the clout wielded by religious militants in Pakistan — particularly by Lashkar-i-Taiba, a violent group that Pakistan once sponsored as a proxy army against India. For months after the three days of violence in Mumbai that killed 166 people, the Pakistani government denied that the terrorists were Pakistanis.

Most of the evidence was obtained in India, including the confession of Ajmal Amir Kasab, the only suspect captured alive there, and tapes of cellphone calls from Pakistan to the attackers. India made some material available and Pakistani investigators found other evidence, but both governments have resisted sharing the intelligence and accused each other of foot-dragging tactics.

“Ninety percent of evidence required for successful prosecution is already with Pakistan,” said B. Raman, an Indian security analyst. “They may say India has not given more, but they are not sincerely interested in pursuing it.”

The case has consumed more than 80 closed-door hearings in a Pakistani anti-terrorism court at Adiyala jail in Rawalpindi city, inviting “the impression that they are avoiding real action,” Raman said.

Prosecutors here declined requests for interviews, but in brief comments after hearings, they have expressed frustration at the delays and at their lack of access to Kasab, who was videotaped carrying an assault rifle through the mayhem of Mumbai. Last week, the judge rejected a request to issue an arrest warrant for him, saying that because he was in Indian custody, he could not be considered a fugitive. Last May, an Indian judge sentenced Kasab to death.

An influential detainee

Efforts to prosecute a far more important detainee, Zaki-ur-Rehman Lakhvi, have been bedeviled by the influence he wields as a leader of Lashkar-i-Taiba. Indian investigators say he was operations chief of the Mumbai assault. Pakistani police arrested him in 2009 under international pressure, but experts said his religious influence and fame in Pakistan as a combatant in the disputed territory of Kashmir have made authorities reluctant to put him on trial.

“This is a very difficult fish for them to fry,” said one Western analyst, speaking on the condition of anonymity. He described the Pakistani government as wanting to show that it is tough on international terrorism but also wanting to remain “engaged” with the group in hopes of maintaining some control over it.

Intimidating presence

Now reincarnated as Jamaat-ud-Dawa, a religious charity, Lashkar-i-Taiba enjoys a large following among Muslim youths and poor Pakistanis because of its work in crises such as last summer’s floods. Its longtime leader, Hafiz Sayeed, has been repeatedly arrested but then released by Pakistani courts, and he can be heard on many Fridays preaching anti-American sermons at his mosque in the city of Lahore.

Yahya Mujahid, a spokesman for Sayeed, denies that his organization had anything to do with the Mumbai attacks and often points out that Sayeed has never been convicted of a crime in Pakistan.

“All of our problems are because of American pressure. They don’t distinguish between violent and nonviolent organizations,” Mujahid said in a recent interview. Arriving several hours late, he said he had been organizing assistance to victims of a rural dust storm.

Despite its benign new identity, Pakistani analysts said Lashkar-i-Taiba is still an intimidating presence here in Punjab province, where judges and politicians tend to appease religious extremists. And although the federal government has a strong anti-terror law and a well-trained federal investigative service, it often lacks the resources and support to win in court.

A cordial meeting between the Indian and Pakistani prime ministers at a cricket match last week was the latest in a series of diplomatic overtures. Pakistani and Indian officials agreed to open a terrorism “hotline,” and Pakistan said it would allow Indian investigators in the Mumbai case to visit Pakistan for the first time. But no dates were set, and there was no progress on Indian officials’ requests to meet the Pakistani detainees or test their voice identities against cellphone calls to the attackers from their alleged handlers in Pakistan.

Pakistani officials, while insisting they want to get to the bottom of the Mumbai attacks, acknowledge that they are not in a strong position to crack down on Lashkar-i-Taiba, and they express resentment over continuing U.S. pressure on the issue. They note that Pakistan has been victimized by terrorism for years and has provoked public antagonism by allowing U.S. cross-border missile attacks on suspected militants.

“Mumbai must have been terrible, but we have suffered many Mumbais,” said Foreign Secretary Salman Bashir. “All of us want to free the region of this lethal virus, but it does not help to stigmatize us.”

Correspondent Rama Lakshmi in New Delhi contributed to this report.