Under pressure from lawmakers including members of his own party, Pakistan's president on Monday signed a regulation that puts a northwest valley under Islamic law to achieve peace with Taliban militants who have brutalized the area. Meanwhile, authorities announced the arrest of a fifth suspect in the deadly siege of the Indian city of Mumbai last year. The provincial government in northwestern Pakistan agreed in February to impose Islamic law in the Swat Valley and surrounding areas in exchange for a cease-fire with the local Taliban. Western and Pakistani critics say the agreement represents a dangerous surrender to extremists behind a campaign of terrorism in the Swat Valley and more broadly across the border region with Afghanistan. Amid the criticism, Zardari delayed signing the agreement.