BOSTON — Dozens of billboards with Muslim themes are sprouting nationwide, proclaiming what organizers say is the true message of Islam and its prophet, Muhammad: peace and justice, not extremism and violent jihad. The New York-based Islamic Circle of North America has erected 100 new billboards over the summer in cities including Boston; New York; Phoenix; San Diego; El Paso and Austin, Texas; Memphis, Tennessee; Cleveland; Las Vegas; Milwaukee; North Bergen, New Jersey; Portland, Oregon; Harrisburg, Pennsylvania; Denver; and Calgary, British Columbia. They feature statements such as: "Muhammad believed in peace, social justice, women's rights" and "Muhammad always taught love, not hate; peace, not violence." Also listed are a website and a phone number people can call for more information. The group's president, Naeem Baig, said the idea for the campaign arose after January attacks in Paris by Islamist militants on the French satirical weekly Charlie Hebdo and a kosher grocery store killed 20 people, including the three attackers. The perpetrators wrongfully understood the teachings of the Prophet Muhammad, Baig said, and the American Muslim community wanted to reclaim the message. As for whether the campaign would face a tougher audience in Boston, with the 2013 Boston Marathon bombings still fresh in many people's minds, Baig said: "That's the whole point of the campaign; there are extremists in all communities." Muslim brothers Tamerlan and Dzhokhar Tsarnaev carried out the attack at the marathon finish line that killed three people and wounded more than 260 others. Prosecutors said the bombings were intended to punish the U.S. for its wars in Muslim countries. "As a Muslims, it hurts me when I see someone abusing my faith, abusing the teachings of the prophet," Baig said. He sees those who resort to violence "as people who are lost, who have no direction in their life, people who have their own challenges in their life, who are using faith as an excuse." Bilal Siddiqui, a college student who volunteers for ICNA in Boston, said some callers vent and "spew hatred." But after speaking to a knowledgeable person on the hotline, "oftentimes their approach becomes softer and they're more keen to learn more," he said. Wilherm Edward, a non-Muslim who works at an auto parts store situated near one of the three Boston billboards, said he thinks the campaign is a great idea. Edward's line of work, he said, exposes him to people from all walks of life, including Muslims. "All the ones I've seen, they're all good people," he said. While praising the billboard campaign as a "laudable effort," the leader of Boston's biggest mosque said his institution prefers to take a different approach. "We feel our actions speak louder than words," said Yusufi Vali, executive director of the Islamic Society of Boston Cultural Center. The group aims to live the faith's values through its food pantry and its work on affordable housing and criminal justice, Vali said. "People appreciate your being real a lot more than the messaging and marketing," Vali added. "I think the way we change people's hearts is through our actions and deeds."