Pakistani authorities said Monday three U.S. drone strikes killed at least 18 militants in Pakistan's northwest tribal region, including several Arab nationals and suspected militant leaders.

The authorities said all the strikes took place in South Waziristan and hit a compound, an Islamic seminary and a vehicle near the region's main town of Wana.

The attacks came three days after the reported death of senior al-Qaida operative Ilyas Kashmiri in another U.S. drone strike in the same area.

Pakistan's Prime Minister Yousuf Raza Gilani and Interior Minister Rehman Malik both said Monday they were confident Kashmiri is dead, with Malik saying he was “100 percent sure.” However, independent confirmation is difficult because no body has been recovered.

Prime Minister Gilani also said intelligence gathering between Pakistan and the United States is returning to previous levels, following a breakdown after the May 2 U.S. raid that killed al-Qaida leader Osama bin Laden in the northern city of Abbottabad.

In Washington Monday, the director of Center for Peace and Security Studies at Georgetown University, Bruce Hoffman, told VOA Kashmiri's reported death is significant because it deprives al-Qaida of yet another person to whom it would have turned to implement a campaign of vengeance.

The United States has designated Kashmiri a “Specially Designated Global Terrorist” and offered a $5 million reward for information leading to his capture. The al-Qaida operative is accused of involvement in several attacks on Western targets, the 2008 terrorist siege on the Indian city of Mumbai, and the recent attack on a Pakistani naval base in Karachi.

This is the second time Kashmiri has been reported to have been killed. Pakistani officials had earlier said that Kashmiri was killed in a suspected U.S. drone strike in September 2009.