Two suicide bombers killed 43 people in near-simultaneous blasts Friday, the fourth major attack in Pakistan this week and a clear sign that militants have the power to strike targets despite months of army offensives and U.S. missile strikes.

The bombings in Lahore, which also wounded about 100, raised fears of a new wave of attacks by Islamic militants. With no explanation of why the violence is surging now or how long it could last, Pakistanis have been left to guess at how bloody the situation could get.

“This is an attack against our people, our country,” said senior Lahore official Sajjad Bhutta, calling on law enforcement agencies to improve their intelligence networks.