The lead Democratic US senator working on bipartisan gun safety talks following a wave of mass shootings said on Sunday he thinks a package including investments in mental health and school safety and some changes to gun laws can pass Congress.

“Do some significant mental health investment, some school safety money and some modest but impactful changes in gun laws. That’s the kind of package we’re putting together right now,” US Senator Chris Murphy said in an interview on CNN, adding he was unsure whether a Senate vote on gun safety legislation could be held this week.

A bipartisan Senate group led by Murphy and Republican Senator John Cornyn of Texas has been discussing whether to tighten gun safety laws after the deadliest school shooting in nearly a decade, in which 19 children and two teachers were killed at an elementary school in Texas nearly two weeks ago. The shooting in Uvalde, Texas, came days after a gunman killed 10 people at a supermarket in Buffalo, New York.

Democrats control razor-thin majorities in Congress but Senate rules mean they need at least 10 Republicans to pass major legislation. That is a tall order with less than six months before November mid-term elections when Republicans aim to retake the majority.

Murphy, of Connecticut, where a gunman killed 26 children and educators at the Sandy Hook Elementary School in 2012, said parents in his state are worried.

“There’s just a deep fear for our children right now. And also a fear that government is so fundamentally broken that it can’t put politics aside to guarantee the one thing that matters most to adults in this country — physical safety of their children,” he said.