WASHINGTON: The US administration came to the brink of saying sorry at the Salala Chechpost attack in Pakistan several times, according to a report published in the Wall Street Journal on Friday.

However, The fight of Secretary of State Hillary Clinton was aborted while she was on mission to deliver an official apology over the assassination of two dozens Pakistani soldiers.

After nearly six months, officials at the highest reaches of the Obama administration have been locked in a heated debate over what might appear to be a small step -- apologizing for the loss.

The U.S. had expressed "regret" for the Nov. 26 deaths. But whether to publicly apologize, at the risk of appearing weak to Pakistan or American voters, was argued in dozens of video conference calls, nearly 20 high-level White House meetings and hundreds of confidential emails.

Pakistan kept closed an important supply route for U.S. forces in Afghanistan while waiting, with the delay extracting a steep price that U.S. officials say will only go up. Islamabad this week indicated that it would reopen the supply route in return for up to a 30-fold increase in the passage fees, officials said. The U.S. last year moved 35,000 shipping containers through Pakistan, paying the country nearly $200 in fees for each, congressional officials said.

The drawn-out debate shows how the U.S. remains confounded by efforts to repair relations with Pakistan. It was complicated by election year politics. And it revealed tensions within the Obama administration's national-security team, which on issues involving Afghanistan and Pakistan has struggled to reach consensus and deliver a coordinated message.

Advocates of apology, in particular among U.S. diplomats, said it was the best way to mend relations. Opponents said it would be interpreted as U.S. weakness just as Washington wanted to pressure Pakistan to root out militant havens along its border, including those launching attacks on U.S. troops.

This account of the diplomatic tug of war is based on interviews with nearly a dozen current and former officials of the Obama administration, as well as Pakistani officials.

The debate began almost immediately after Nov. 26 last year. On that day, a 150-man U.S.-Afghan commando team near the Pakistan border came under attack and called in air support, according to U.S. officials.

U.S. helicopters fired on two Pakistani border posts. The Pentagon said Pakistani troops at the posts opened fire first, which Pakistan has denied. Pakistan has accused the U.S. of deliberately firing at its troops.

For Pakistanis, the killings were another U.S. affront to national pride. Only seven months earlier, the U.S. sneaked elite special forces into the country to kill Osama bin Laden. An immediate apology, Pakistani officials argued in November, would ease tensions and ward off protests.

The U.S. military believed an immediate apology amounted to an admission of fault. Even so, the Pentagon privately told Pakistan it was prepared to pay restitution to the families of those killed. Pakistan rejected the cash without an apology.

Vali Nasr, a former top adviser on Pakistan in the Obama administration, said people in Pakistan interpreted the U.S. refusal to apologize to mean "it intended to kill the 24 people."

At the White House, officials rejected the first of several apology proposals, including one that called for President Barack Obama to personally deliver a condolence message to the Pakistani people.

In late December, the Pentagon released its investigation. The U.S. concluded both American and Pakistan troops erred. Islamabad rejected the finding.

On Dec. 21, the night before the Pentagon's investigation was released, top U.S. policy makers convened for a 5 p.m. secure video teleconference and agreed to apologize. Defense Secretary Leon Panetta wasn't enthusiastic but didn't object, Jeremy Bash, Mr. Panetta's chief of staff, told the group, according to officials.

Though divided about apologizing, defense officials wanted border supply crossings to reopen as soon as possible. The U.S. and NATO allies had to route shipments through a northern route through Russia, Central Asia and the Caucasus, which cost 2½ times more per container than going through Pakistan, according to Pentagon estimates.

Under the Dec. 21 plan, Pentagon press secretary George Little would issue an apology the next morning. "We mourn the loss of life and apologize for the weaknesses in our border coordination processes which contributed to this tragic accident," one early draft read.

Mr. Bash reported that top policy makers at the White House and the Pentagon had reversed course. White House National Security Adviser Tom Donilon was among the officials who asked that the word "apologize" be replaced by "deepest regret" and "sincere condolences." Mr. Panetta helped draft the changes, officials said.

In the hours that followed, State Department and some Pentagon officials urged the White House to reconsider the decision, arguing that "apology" would make a critical difference with Pakistan and wasn't much different from "regret."

U.S. Ambassador to Pakistan Cameron Munter told the group an apology would increase the chances of persuading Pakistan to reopen the border crossings.

Mrs. Clinton's chief policy aide, Jake Sullivan, told colleagues the U.S. should acknowledge its mistakes. He argued that an apology would strengthen Washington's hand in pressing Pakistan to step up its fight against militants, according to officials in the debate.

Michele Flournoy, then the undersecretary of defense for policy, suggested language that apologized for the "unintentional and tragic" deaths but didn't accept full responsibility, officials said. Ms. Flournoy, who has since left the administration, told the group the U.S. risked the issue festering.

On Dec. 22, Mr. Little, the Pentagon spokesman, read the revised expression of "regret" but without an apology.

On Feb. 21, the White House approved a new plan. Army Gen. Martin Dempsey, the chairman of the Joint Chiefs of Staff, would apologize by phone to Gen. Kayani the next day. Mrs. Clinton was scheduled to meet with Pakistani Foreign Minister Hina Rabbani Khar in London.

An official close to the Pakistan government likewise lamented: "If the apology would have occurred in the first or the second day, as it should have, we could have moved on."