CAIRO — Softening his tone, al-Qaida leader Osama bin Laden issued a humanitarian appeal on Saturday urging Muslim governments to do more to help Pakistan’s flood victims and expressing worry about climate change. It was his second purported audiotape in as many days.

The less aggressive approach contrasted with al-Qaida’s previous calls for a violent response in what experts say could be a "good cop, bad cop" ploy to exploit anger over the flooding and rally support for the terror network.

Al-Qaida is under pressure to refurbish support among Pakistanis as it faces a surge in U.S. missile strikes and government crackdowns on insurgents who easily move between Afghanistan and Pakistan’s porous border. American officials have asserted for months that the core of the network has been weakened and is struggling to raise money and attract recruits.

Bin Laden, who is believed to be hiding in the lawless border area that separates the two countries, said governments of Muslim nations have not done enough to help Pakistanis hit by devastating floods that killed hundreds and affected about 20 million people this summer.

"The effort should have been bigger from the beginning," he said in a recording posted Saturday on militant websites. It was distributed along with a photograph of a smiling bin Laden superimposed over pictures of flood victims.

He also singled out Arab leaders, accusing them of failing to respond to a calamity in a fellow Muslim nation and asserting that the U.N. secretary-general did more than them to help Pakistan.

Bin Laden has often sought to package himself as a senior statesman. In this recording, he assumed a tone more measured than past videos and recordings in which he and his deputies called for the leaders of Muslim nations like his native Saudi Arabia to be overthrown.

Experts said he was likely trying to broaden al-Qaida’s appeal beyond its traditional extremist support base while remaining devoted to the network’s campaign of violence.

The messages coincided with reports that bin Laden was behind the terror plots to attack several European cities. If true, that would be the most operational role that bin Laden has played in plotting attacks since Sept. 11, 2001.

"Bin Laden is dancing above the fray and addressing broader issues that give him the appearance of a benevolent father figure to embattled Muslims," said Evan Kohlmann, a terrorism analyst with Flashpoint Global Partners, a New York-based security consultancy. "Perhaps bin Laden sees this as a way of swaying those on the edge towards supporting him."

A copy of the 13-minute, nine second audiotape, entitled "Help your Pakistani Brothers," was made available by the U.S.-based SITE Intelligence Group, which monitors jihadi forums. Its authenticity could not be independently confirmed, though the voice resembled that of bin Laden in previous confirmed messages.

In a similar recording released Friday, bin Laden called for the establishment of a relief organization to prevent flooding in Muslim nations, create development projects in impoverished regions and improve agriculture to guarantee food security.

U.S. and Pakistani officials have often expressed fears that militant groups in Pakistan could drum up support by exploiting frustration among Pakistanis who feel aid has not reached them quickly following the floods that swept through the country starting in late July.

Asked about Friday’s bin Laden message, White House press secretary Robert Gibbs said he doubts the victims in Pakistan would be "comforted in getting the aid that is necessary from somebody that is not showing their face to the world."

The U.N.’s humanitarian arm said last week that most of those displaced by the floods have begun returning to their homes. But Pakistanis remain deeply unhappy with the government’s performance after the deluge despite official insistence that any government would have had problems responding to a crisis of that magnitude.

Two earlier al-Qaida videos about the floods took a sharp militant tone.

A U.S.-born al-Qaida spokesman, Adam Gadahn, urged Muslims in Pakistan to join Islamist militants fighting their nation’s rulers in a video last week, saying that Islamabad’s "sluggish and halfhearted" response to recent floods showed it did not care for them.

Before that, al-Qaida’s No. 2 leader, Ayman al-Zawahri, made a thinly veiled call on Pakistanis to rise up against their government over what he said was the "failure" of authorities there to provide relief to flood victims.

Bin Laden often takes a more elevated, philosophical stance than his deputies — opining, for example, on global warming in past messages. However, in his last audiotape released in March he threatened retaliation if the U.S. executes Khalid Sheikh Mohammed, the self-professed architect of the Sept. 11 terror attacks.

Bruce Hoffman, a terrorism expert at Georgetown University, said bin Laden could be taking advantage of renewed publicity over the European terror plot to thrust himself back in the spotlight. The accusations have raised speculation bin Laden might be seeking to show al-Qaida’s besieged Pakistan-based core remains able to launch attacks on Western targets.

"It may be their way of doing good cop, bad cop and making sure that all of al-Qaida’s messages are being communicated," he said. "In other words, they’re covering all bases."

In Saturday’s message, bin Laden accused the media of failing to cover the flooding tragedy effectively or provide "the real picture" of natural disasters in the Muslim world. Journalists should also increase coverage of climate change, he said.

International donors have pledged more than $800 million for flood relief in Pakistan, the bulk of it coming from the United States which has donated nearly $350 million. The United Nations last month hiked up its call for aid, seeking to raise $2 billion for Pakistan’s flood victims, its largest humanitarian appeal ever.

Arab nations in the Gulf, including Saudi Arabia and the United Arab Emirates, have also launched relief appeals and delivered aid to Pakistan.

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