"Obviously, we are deeply concerned," Obama told reporters as he met British Prime Minister Gordon Brown after attackers armed with guns and grenades killed eight people and wounded seven members of the Sri Lankan squad in Lahore.
Saying "the details are still coming in so I don't want to be too specific," Obama wanted instead to make a general point about joint US-British efforts to keep terrorism at bay.
"Both Great Britain and the United States share a deep interest in ensuring that neither Afghanistan or Pakistan are safe havens for terrorist activity," the president said.
He said the "truth is that the situation in Afghanistan has deteriorated" even though Washington and London have cooperated well to improve conditions as the first and second biggest foreign troop contributors there.
"The safe havens for Al-Qaeda remain in the frontier regions of Pakistan," Obama said, referring to the other side of the Afghan border.
He recalled that Washington is conducting a comprehensive review of its policies to Afghanistan and Pakistan in co-ordination with the Nato (North Atlantic Treaty Organization) and other military allies in Afghanistan.
"I will be making a series of announcements prior to the Nato summit that immediately follows the G20 summit in terms of the direction that the United States would like to go," he said.
The Group of 20 developing and developed countries summit is due to be held in London on April 2. The NATO summit is scheduled to take place April 3-5 in Strasbourg.
Gordon Duguid, a State Department spokesman, earlier denounced the attack in Lahore as one aimed at harming innocent civilians as well as undermining relations between Pakistan and its south Asian neighbor Sri Lanka.
"This is not just an attack on individuals. This is an attack on peaceful, normal relations, and we utterly condemn this terrorist attack," Duguid said.
There was no immediate claim of responsibility although fears of an attack by Islamic militants linked to Al-Qaeda have caused many cricket teams to cancel tours to Pakistan in recent years.
Pakistani officials said the attack bore all the hallmarks of the November 2008 assault on the Indian city of Mumbai, which was blamed on Pakistan-based Islamic militants.
It was the first deadly assault against a sports team in nuclear-armed Pakistan, where more than 1,600 people have died in a wave of Islamist attacks in 21 months, and where Al-Qaeda and Taliban shelter in its northwest.