President Asif Ali Zardari was set to leave Wednesday for an overseas visit, a week after the assassination of his close allyexposing the president to renewed criticism for ignoring the country's myriad problems. Critics are comparing this unofficial trip to the U.S. with Mr. Zardari's absence last year at the height of the country's massive flooding, which affected more than 20 million people. Mr. Zardari is expected to arrive in Washington Thursday to attend a memorial service Friday for Ambassador Richard Holbrooke, the veteran U.S. diplomat who was President Barack Obama's special representative for Afghanistan and Pakistan. But a worsening security and economic situation in Pakistan has triggered widespread protests. A recent patch-up with an estranged ally may have prevented a possible fall of the government, but the ruling coalition is still hanging together by a thread. Many more people are taking to the streets protesting ballooning inflation and power and gas shut-offs. The assassination last week of Salman Taseer, governor of Punjab, Pakistan's most populous province, and public support for the killer has exposed a dangerous ideological chasm in the country. Mr. Taseer was shot dead in an upscale shopping area in Islamabad by his bodyguard, who accused the governor of speaking against the blasphemy laws. The rise of religious violence, along with the dire economy and deepening political unrest, are threatening the stability of the nuclear-armed nation, which is a serious concern to the U.S. U.S. Vice President Joe Biden, on a visit to Islamabad, said Wednesday that Taliban and al Qaeda elements living in the remote, lawless areas of the country's northwest were a threat to Pakistan. "A close partnership between Pakistan and its people is in the vital self-interest of the United States of America and, I would argue in the vital self-interest of Pakistan as well," he told reporters after a meeting with Prime Minister Yousaf Raza Gilani. Mr. Biden arrived in Islamabad after two days in Kabul, where he said Pakistan needed to do more to help the U.S. in its battle against Taliban and other militants in Afghanistan as it prepares to withdraw its troops from there. The U.S. vice president also held talks with President Zardari and Pakistan's army chief, Gen. Ashfaq Kayani. In Washington, Adm. Mike Mullen, chairman of the U.S. military's joint chiefs of staff, reiterated Mr. Biden's urging that Pakistan should do more to crack down on militant havens. "We cannot succeed in Afghanistan without shutting down those safe havens," he told reporters. His unusually blunt comments underscored growing U.S. frustration with Pakistan over its reluctance to step up its offensive. "I'm confident that the [Pakistani] military knows what it has to do and intends to do this," Adm. Mullen said, but he offered no time frame. While pushing Pakistan's military to intensify action against the militants, the U.S. has stepped up drone strikes targeting al Qaeda and Taliban sanctuaries in the tribal regions along the border with Afghanistan. On Wednesday, missiles fired by a pilotless predator in North Waziristan killed four people, a Pakistani intelligence official said. In a separate incident Wednesday, two female teachers were killed when two roadside bombs exploded close to a van carrying schoolchildren near Peshawar. And in Bannu, in Pakistan's volatile northwest region, a suicide car bomber devastated a police station and adjoining mosque, killing 18 people and wounding 25. The blast badly damaged the police station and the mosque, trapping many victims under the rubble. Following Mr. Zardari's three-day stay in Washington, where he is expected to meet top American officials, the Pakistani president will go to London and Dubai, keeping him out of the country for more than a week. A presidential spokeswoman said Mr. Zardari is going to pay homage to Mr. Holbrooke, who she said was a great friend of Pakistan. "The visit will help strengthen the ties between the U.S. and Pakistan," said Farahnaz Isphani, adding that Mr. Zardari's absence won't have any political fallout at home. But analysts said Mr. Zardari's absence at such a critical time won't help his image, which has already hit a low amid a growing perception that his government has failed to bring political and economic stability. Mr. Zardari doesn't face any immediate threat of being ousted from power, despite the deepening crises, as neither the opposition nor the military want to take over at such a critical stage. Analysts say the Zardari government is surviving by default. The military, which has directly or indirectly ruled the country for most of its history, is preoccupied with fighting the Taliban in the north. "Although it may not have any serious political implications, the absence of the president from the country at this stage may not go down well among people," said Rafaat Husain, a professor at Quaid-e-Azam University in Islamabad. A senior Pakistani official said that during his U.S. visit, Mr. Zardari would seek American economic help for Pakistan. Washington has already committed to giving Pakistan $7.5 billion in aid in the coming years for improving infrastructure and for other sectors. But analysts say there is little hope of any additional U.S. aid, particularly after the government backtracked on its planned economic overhauls. Last week, under pressure from both allies and the opposition, the government rolled back an unpopular increase in fuel prices and deferred the implementation of a sales tax. The moves will further increase an already high budget deficit to 8%, against a target of 4%. The development has also derailed the overhaul program agreed with the International Monetary Fund. The fund has withheld $3.5 billion from a total loan package of $11 billion.(WSJ)