Sen. John Kerry talks with Hussain Haqqani, Pakistan’s ambassador to the United States, in Islamabad on Monday. (B.K.Bangash/AP)

Pakistan has agreed to return the tail of the U.S. military helicopter that was damaged during the raid that killed Osama bin Laden, Sen. John F. Kerry (D-Mass.) said here Monday, part of what he called a “specific series of steps” aimed at reducing tensions between Islamabad and Washington.

The helicopter was damaged after making a hard landing at bin Laden’s compound. Navy SEALs destroyed part of it before leaving, in an effort to keep the latest U.S. military technology a secret. But the tail remained intact, and photos of it quickly made their way into public view. In the days after the operation, Pakistani intelligence officials said China had expressed interest in it.

The handover of the helicopter tail, to be made Tuesday, is one result of several high-level meetings Kerry said he held with Pakistani officials to alleviate strains between the two allies. The long-fraught relationship has reached one of its worst points after U.S. commandos killed bin Laden in a Pakistani garrison city.

Pakistan has chafed at not being informed of the raid in advance, while U.S. officials have openly questioned whether Pakistani officials colluded with bin Laden.

Kerry sought Monday to play down those allegations, saying he was in Pakistan to “recalibrate” the relationship, not judge whether Pakistan harbors terrorists. But he said he and Pakistani officials had discussed several points of contention, including Pakistan’s alleged support for Afghan insurgents based on its soil and for Lashkar-i-Taiba, a Pakistani militant organization that has been accused of carrying out attacks in India and Afghanistan.

Kerry, whose name is attached to a major U.S. economic assistance package to Pakistan, said he conveyed to the Pakistanis that they must demonstrate a commitment to fighting Islamist militancy to address the concerns of members of Congress who, after the bin Laden killing, have called for the end to U.S. aid.

“The make-or-break is real,” said Kerry, who is chairman of the Senate Foreign Relations Committee and the most senior U.S. envoy to visit Pakistan since bin Laden’s death. “There are members of Congress who aren’t confident that [the relationship] can be patched back together again. That is why actions, not words, are going to be critical to earning their votes.”

Kerry did not specify other steps agreed to during his meetings, although he said commitments were made to increase U.S.-Pakistan intelligence sharing and joint intelligence operations — areas that had come to a near standstill in recent months. A joint U.S.-Pakistan statement issued Monday said the countries would cooperate in operations against “high-value targets” in Pakistan.

In coming days, senior White House officials will visit Pakistan to discuss implementation of what Kerry called the “road map.” Those discussions will determine whether Secretary of State Hillary Rodham Clinton will move forward with plans to visit Pakistan this month, said Kerry, although he suggested there is little prospect that the nations would break ties.

The United States uses Pakistan as a key supply route for U.S. troops in Afghanistan, and Pakistan’s assistance is viewed as crucial to a potential negotiated end to the war there. At worst, some U.S. officials say, cutting ties with Islamabad could destabilize the government to the point that Pakistan’s nuclear arsenal falls into the hands of Islamists.

Pakistan, meanwhile, needs U.S. assistance to help arm its military and shore up its teetering economy. And although anti-U.S. sentiment is widespread, Pakistan also depends on the cachet of being allied with a superpower — particularly in view of poor relations with its neighbors.

On Tuesday, Pakistani Prime Minister Yousaf Raza Gillani began a four-day visit to China, an old, trusted ally of Pakistan with superpower aspirations of its own.

A continued downward spiral in U.S.-Pakistan ties, Kerry said, “is a very dangerous road for everybody — dangerous for Pakistan, dangerous for our interests, dangerous for the people of this country and for the region.”

In recent days, Pakistani civilian and military officials have coalesced around anger about the bin Laden raid, which they characterize as a violation of sovereignty. On Friday, Parliament passed a resolution condemning the operation, calling for an end to CIA drone strikes and threatening to cut off NATO supply routes through Pakistan.

Kerry said he emphasized to Pakistani leaders that the secrecy surrounding the Abbottabad operation was not a reflection of U.S. distrust. Having narrowly failed to reach bin Laden in Afghanistan in 2001, the United States was determined this time to avoid leaks at all costs, Kerry said, and few senior U.S. officials were told in advance about the raid.

“My goal in coming here was not to apologize for what I consider to be a triumph against terrorism,” Kerry said of the raid on bin Laden’s compound. He added: “Faced with a second chance to capture Osama bin Laden, no American president could conceivably have afforded to take even the slightest chance that he might again slip through our hands.”

The joint statement said Kerry had also assured Pakistan that the United States has “no designs” on its nuclear arsenal. It did not mention drone strikes, which Pakistan tacitly allows but publicly protests. One such strike in the border area of North Waziristan killed seven people Monday, according to the Associated Press.

The militant threat in Pakistan was highlighted earlier in the day in the southern port of Karachi, where gunmen on a motorbike fatally shot a Saudi diplomat as he was driving. A senior police official in Karachi said investigators were trying to determine whether militants related to al-Qaeda, which opposes the Saudi regime, had carried out the attack to avenge the killing of the Saudi-born bin Laden.

But the official said the assassination of the diplomat, which came two days after hand grenades were lobbed at Saudi Arabia’s consulate in Karachi, might also have been carried out by Shiites angry that the kingdom had sent troops to Bahrain to suppress Shiite protests there.

Special correspondent Shaiq Hussain contributed to this report.