(MCT) — WASHINGTON — Pledging to “put everything I’ve got into this,” a somber President Barack Obama challenged Congress on Wednesday to approve an extensive package of gun control proposals that he said would help prevent mass shootings and reduce the epidemic of gun violence.

The president’s response to the December massacre at a Connecticut school included renewing the expired ban on sales of assault-style weapons and high-capacity ammunition magazines, plus expanding background checks of gun buyers. Those measures will face strong opposition in Congress from most Republicans and some Democrats, making prospects for passage highly uncertain.