The 40-year-old blogger was attacked by four suspected Al Qaeda linked Islamists at their apartment
"It requires recognition that we will not just solve these problems militarily, but we're also going to have to be much more effective diplomatically; we're going to have to be much more effective on the development front," he said.
Zawahiri served three years as a surgeon in the Egyptian Army, but his journey from an eye surgeon to becoming a most wanted global terrorist started after he met Laden in 1986, and joined Laden as his personal advisor and physician.
Security was beefed up at all railway stations in Lucknow even though the letter seemed to be a hoax.
A Financial Times report says that Tokyo, Sydney or Singapore could be the probable targets.
The Obama administration hopes to get a treasure trove of information from the materials, including a computer hard drive and disks, recovered from the hideout of Al Qaeda chief Osama bin Laden, who was killed in a United States military operation in Pakistan.
Dr Singh said the "international community and Pakistan in particular must work comprehensively to end the activities of all such groups who threaten civilised behaviour and kill innocent men, women and children".
Security forces have launched an operation against foreign terrorists near Zarodai in the tribal agency area, Information Minister Sheikh Rashid was quoted as saying by the state-run PTV.
"We should not underestimate the Taliban and Al-Qaeda nor fight terrorism with any less military and political determination than in the immediate post-2001 days after terrorist attacks on the United States," India's UN Ambassador Nirupam Sen told the Security Council on Wednesday.
Modi regretted that the international response to terrorism was weak and said more cooperation was needed to fight the menace.
Some Al Qaeda operatives used New Delhi-based global missionary movement Tablighi Jamaat to get visas and fund their travel to Pakistan and lived for a while in and around New Delhi, secret US documents released by WikiLeaks say.
The warning of a potential attack by Al Qaeda in the Arabian Peninsula was received 'in the last few hours', the French Interior Minister Brice Hortefeux told a European television network.
There is no threat from either Al Qaeda or ISIS of a magnitude which the country cannot deal with, National Security Advisor Ajit Doval said on Tuesday but asserted that security agencies were keeping a "very close watch".
Resolve Palestinian issue to defeat Al Qaeda: Musharraf
Adm Michael Mullen, chairman of the US joint chiefs of staff, said despite the scale of threat, progress would be slow since Pakistan has been lagging behind in its strategy to eliminate safe havens for terrorists in the lawless Federally Administered Tribal Areas
But they have little proof that the eight suspects arrested in Pakistan and England were preparing to hit targets in the US.
Mohammad Naeen Noor Khan was being used by Pakistan in a sting operation against the Al Qaeda.
"Al Qaeda is especially notable for its longstanding interest in weapons-usable nuclear material and the requisite expertise that would allow it to develop a yield-producing improvised nuclear device," said John Brennan, the Deputy National Security Advisor for Counter-terrorism and Homeland Security, on Monday.
With the Al Qaeda on the back foot, Hafeez Saeed-founded Lashkar-e-Tayiba has emerged as the world's most dangerous terror group and has connections with Pakistan's Inter-Services Intelligence and army, a former senior Central Investigation Agency officer has said.
The United States of America sought Pakistan's help in 1998 to prevent Osama bin Laden from launching an Al Qaeda attack against it, with then President Bill Clinton asking Prime Minister Nawaz Sharif to personally use his influence to prevail over the Taliban in averting the imminent strike.
America's CIA is running a 3,000-strong covert army to hunt down key leaders of Taliban and Al Qaeda in not only Afghanistan but across the border in Pakistan.
They had been air-dropped in areas held by Al Qaeda militants in the south Waziristan tribal region bordering Afghanistan.
The New York City continues to be at the risk of a terror attack even after the killing of Al Qaeda's longtime chief Osama bin Laden, the city police chief has said.
A majority of Pakistanis still consider India as a major threat, view America as an enemy and are far less concerned about the Taliban and the Al Qaeda
A senior member of Islamic militant group told U.S. authorities that the group had drawn up a plan to launch attacks in Japan during the 2002 event.
Nasir Al-Wuhayshi, 32, was a key member of the Al Qaeda. He received jihadi training directly from Al Qaeda founder Osama bin Laden in Afghanistan.
The agency said it has found several digital devices containing large volumes of incriminating data during the searches.
Professor Clive Williams, of the Centre for Policing, Intelligence and Counter Terrorism at Macquarie University, New South Wales, said the threat should be seen as a deliberate ploy to destabilise India, and warned that if its warning was not heeded, action could follow soon.
They could try to disrupt Republic Day celebrations or target Advani and some other leaders, Special Commissioner of Delhi police (Security) S K Kain said.
The Al Qaeda's second in command, Abu Yahya al-Libi, was the main target of the United States drone strike that killed 15 militants in Pakistan's lawless Northwest on Monday and US officials said they were "optimistic" the Libyan had not survived
Former Pakistan premier Benazir Bhutto said she does not blame the government for the terrorist attack on her homecoming parade in Karachi.
"An attempt has been made to create a scare among the people. If it merits response, it will be there," Gupta said.
The Pakistan Army, however, asserted that only 'three to four' of its personnel were being held for alleged links with extremist groups.
Al Qaeda and its followers, the New York Times says, have used the Internet to communicate and rally support for years, but in the past several months the Western tilt of the message and the sophistication of the media have accelerated.
The White House has outrightly refused to negotiate with Al Qaeda for the release of its citizen, who was kidnapped by the terrorist outfit in Pakistan last year.