WASHINGTON — President Barack Obama on Wednesday asked a team led by Vice President Joe Biden to offer “concrete proposals” to curb gun violence no later than January, in the aftermath of the massacre at a Connecticut school. “This time, the words need to lead to action,” said Obama, who set a January deadline for the recommendations. The president said he will push legislation “without delay.” He urged Congress to hold votes on the bill next year. “The fact that this problem is complex can no longer be an excuse for doing nothing,” Obama said. “The fact that we can't prevent every act of violence doesn't mean we can't steadily reduce the violence.” The gunman in Friday's shooting wielded a semi-automatic rifle to kill 20 children and six adults at the school, after killing his mother at home. He then killed himself. Obama, who pushed little on gun control during his first term, also pressed Congress to reinstate an assault weapons ban, which expired in 2004. He called for stricter background checks for people who seek to purchase weapons and limited high-capacity clips. Biden, a longtime gun control advocate, will lead a team that will include members of Obama's administration and outside groups. US Representative Ron Barber, who was wounded in a 2011 Arizona shooting that targeted his predecessor Gabrielle Giffords and 18 others, welcomed the effort and echoed other Democratic lawmakers' calls to ban military-grade guns. “I really believe that we can put together a broad coalition to deal with particularly the assault weapons and the heavy firepower that these large capacity magazines contain,” Barber told MSNBC on Wednesday. Friday's massacre was the fourth shooting rampage to claim multiple lives in the United States this year. The president demanded changes to the way the United States deals with gun violence at a memorial service in Newtown on Sunday. Obama said he would “use whatever power this office” holds to prevent such tragedies in the future. Gun control has been a low priority for most US politicians due to the widespread popularity of guns in America and the clout of the National Rifle Association, the powerful gun industry lobby. The constitutional right to bear arms is seen by many Americans as set in stone, and even after mass shootings, politicians have tiptoed around specific steps to limit access to lethal weapons. — Agencies