Small attacks could be done by only a few or even just one person, while at the same time "we must watch and wait to seize any opportunity to direct a large strike on (America), even if that takes years of patience to do it," he said.
"We should bleed America economically by motivating it to continue its huge expenditure on its security as America's weak point is its economy, which already has begun stumbling because of the military and security expenditure," he said. "America is not a mythic power and the Americans, after all, are humans who can be defeated, felled and punished."
He urged the Islamic world to "abandon the dollar and replace it with a currency of other countries that are not taking part in the aggression against us."
On Syria's civil war, al-Zawahri addressed al-Qaida-linked jihadis including many foreign fighters who have taken an increasingly prominent role in the fight against President Bashar Assad's regime. Their rise has caused tensions with more moderate Syrian rebel factions, even escalating to violence and turf battles. The United States and its allies have said they want to build up moderate rebel factions to reduce jihadi influence.
America wants to use "the Muslim people as a means to topple the pro-Iran Baathist regime and install a secular government and peaceful to Israel," al-Zawahri said. It "will try to push the mujahedeen to compromise with the secular factions and the enemies of Islam."
"I warn my brothers in Syria against any compromise with those factions. They have to learn the lesson of Egypt," al-Zawahri said. He was referring to the army-backed overthrow of Egyptian President Mohammed Morsi and his Muslim Brotherhood.
Regarding Egypt his homeland al-Zawahri denounced what he called the "massacre" and 'savage crimes" in the crackdown by authorities on Morsi's Brotherhood and other Islamists. Still, he dismissed Morsi, saying he did not implement Shariah during his year in office and maintained Egypt's relations with Israel. Al-Zawahri said the crackdown targeted not the Brotherhood, but "the Islamic orientation" in general, because "our American enemies realize the dangers of raising the Islamic banner."
The military-backed authorities in Egypt have arrested several thousand Brotherhood members and Islamists. At the same time, the country has seen increasing violence by al-Qaida-inspired militants, who have stepped up attacks on the military and police in the Sinai Peninsula and have begun extending attacks to the capital, Cairo.