Islamabad, Pakistan (CNN)A bomb exploded during a protest in Lahore, Pakistan, on Monday, killing at least 16 people and injuring 59 more, according to government spokesman Malik Ahmad Khan.
Two groups claimed joint responsibility for what officials said was a suicide attack. Jamat-ul-Ahrar, a splinter group of Pakistan's Tehreek-i Taliban (TTP) -- also known as the Pakistani Taliban -- claimed responsibility for the attack in a statement emailed to CNN. In addition, the chief of North Waziristan Agency's Intiqam Waziristan, or the "Avengers of Waziristan," told CNN in a phone call that they were responsible.
Jamat-ul-Ahrar was also responsible for a deadly attack in Lahore less than a year ago. Last Easter Sunday, a suicide bombing at a neighborhood park killed at least 69 people and injured 341 others. Monday's blast occurred at Charing Cross in Lahore, the capital of Pakistan's Punjab province and the second-largest city in the country.
Pakistani Prime Minister Muhammad Nawaz Sharif strongly condemned the blast, according to a statement obtained by CNN, saying that "such cowardly acts cannot deter the resolve of the nation to stand against terrorism and our government is committed to root out this menace."