"People are looking very closely to see whether he is still alive," the officials were quoted by the New York Times as saying.
The Times said a senior Pakistani security source in Peshawar had said, "It looks like he has been killed."
The paper said tribal sources in Mir Ali, where the drone attack occurred, said the Libyan ideologue was either killed or seriously wounded in the strike, which Pakistani officials said killed at least 15 people.
US officials said that Libi, on whose head Washington had put a bounty of US $ 1 billion, had been the target of the missile attack in North Waziristan, the third drone strike in as many days and the deadliest this year.
"If his killing is confirmed, it could be a major blow to the core of the Al Qaeda -- removing the organisation's number two leader twice in less than a year," they said.
Al-Libi took the second in command spot when Egyptian cleric Ayman al-Zawahari took charge of the Al Qaeda after Osama bin Laden's death.
Al-Libi oversaw the terror group's day-to-day operations in Pakistan's tribal areas and maintained links with its regional affiliates.
Top US intelligence officials said that degradation to core Al Qaeda during the past several years had depleted the ranks to such an extent that the organisation could have no replacement for him.
Al-Libi, a Libyan citizen believed to be in his late 40s, has been an influential Al Qaeda commander and made a dramatic escape from a prison at Bagram Air base in Afghanistan in 2005. He was captured in 2002 after Nato forces toppled Afghanistan's Taliban rulers.
He became the international terror network's deputy leader after Atiyah abd al-Rahman, another Libyan national was killed in a US missile strike in North Waziristan last August.
Earlier too, al-Libi had been reported killed after a December 2009 drone strike in South Waziristan.
In the strike in which al-Libi was reported killed, US drones fired two missiles into a compound in the village of Hesokhel, east of Miranshah, the capital of North Waziristan. After the raid, Pakistani officials had said that among the victims had been foreigners, a term often used for Arab terrorists.
