Democratic state representatives in Minnesota staged an overnight sit-in in their house chamber on Thursday after the Republican speaker failed to put a gun violence prevention bill up for a vote.

Samantha Sencer-Mura, a Democratic representative from Minneapolis, first announced the plan on Wednesday from the floor of the state’s house of representatives, giving speaker Lisa Demuth, a candidate for governor, 24 hours to give the bill a vote before the sit-in would start.

The Minnesota senate, controlled by Democrats, narrowly passed the gun violence prevention omnibus earlier this month. The house, where there is a 67-67 vote tie and a Republican speaker in charge, has so far not taken up the bill.

The push for new gun laws came after a school shooting at Annunciation Catholic church last August, where two students were killed and others injured during a school-wide mass. Minnesota also saw the killings of state lawmaker Melissa Hortman and her husband, and the shootings of state lawmaker John Hoffman and his wife, last summer.

The parents of Harper Moyski, a 10-year-old killed in the Annunciation shooting, and other Annunciation students and families have advocated for changes to state laws to prevent gun violence. Fletcher Merkel, 8, was also killed in the shooting.

The bill includes bans on semi-automatic military-style assault weapons and large-capacity magazines, regulations on safe storage of firearms, a ghost-gun ban, modifications for risk protection orders, and provisions for schools to implement threat reporting systems, among other new policies.

Sencer-Mura had set a deadline of 5pm on Thursday. A procedural motion to bring the bill to a vote failed just before 9pm.

The lawmakers participating in the sit-in intended to stay in the chamber overnight, Sencer-Mura said. The local Fox affiliate reported that about 20 Democratic lawmakers intended to participate.

“What is speaker Lisa Demuth so afraid of? The very fact that she’s breaking her promise to Annunciation families to not block the bill from coming to the floor, tells me that she’s afraid it will pass,” Sencer-Mura said in a statement. “She’s afraid that her members are hearing their constituents, and are going to choose to be on the right side of history.

“This is a serious action to fight for serious solutions. Minnesotans deserve to be safe.”

Demuth’s office was contacted for comment.

Also on Thursday, proponents for the gun violence prevention bill delivered a petition by Everytown with more than 7,000 signatures that calls for passing the bill. Students and gun violence survivors spent the day at the state capitol meeting with lawmakers to advocate for the bill’s passage.

Over the past week, advocates for the bill have held actions to call attention to the bill, including a role-play by medical professionals simulating the aftermath of a gunshot injury, a “sing-in” and a pray-in.

The governor, Tim Walz, a Democrat, has pushed for the gun control measures.

Demuth, whose four children were on the school campus during a 2003 school shooting in Cold Spring, Minnesota, has said gun bans are not the right response to the Annunciation shooting.

“When I saw the governor come out and immediately go to gun bans, I thought … oh, this is not the answer,” Demuth told the Minnesota Star Tribune in April. “This is not going to bring these kids back and that’s all these families want.”

Mike Moyski and Jackie Flavin, the parents of Harper Moyski, have talked with Demuth and many other lawmakers as they have pushed for new gun violence prevention laws. They told the Star Tribune that they asked Demuth whether she would allow a bill that banned assault weapons and high-capacity magazines to be put to a vote on the house floor, and that she had told them she would.

Demuth has previously said the bill needed to pass through committees before it could come to the floor. She told a Democratic lawmaker who asked on Wednesday when it would be moving that it was “being reviewed and it will move through at the appropriate time”.

Minnesota’s legislature is in the final days of its legislative session, with adjournment scheduled for 18 May.

The Minnesota Gun Owners Caucus, a pro-gun lobby group, has opposed the bill. In a post on Twitter about the plan for a sit-in, the group said: “Apparently, constitutional rights are now subject to political performance art. No amount of floor theater changes the constitution.”

Erin Maye Quade, a state senator, held a 24-hour sit-in in 2018 when she was a state representative over a lack of action on gun control measures. It ultimately did not lead to new laws to control guns.

Hopes have been raised that next week’s strikes by London Underground drivers could yet be averted, after sources said the RMT union had put out feelers for talks.

The RMT members, almost half of London’s tube drivers, are due to strike for two 24-hour periods from midday on Tuesday and Thursday, closing some lines entirely and bringing widespread travel disruption to the capital until the weekend.

The action follows a similar wave of strikes in April, with more planned for June in the dispute over a planned four-day week working pattern.

No talks have yet taken place and with neither Transport for London (TfL) nor the union apparently willing to alter course, further strikes had appeared inevitable. TfL has warned passengers that many services will not operate next week.

However, a source close to the dispute said that union representatives had now put out feelers to seek a deal, giving TfL a “window of opportunity” to prevent further strikes.

They said that tube drivers were prepared for a long strike campaign of disruption, adding: “It is clear TfL needs to move from its uncompromising position and make some new proposals that do not impose new working conditions that tube drivers will not accept. An opportunity exists for the employer to do the right thing by Londoners and make a reasonable offer to the union.”

With the strike still scheduled to take place, TfL has urged customers to plan ahead and expect significant disruption, with early closures of services on Tuesday and Thursday and late starts on Wednesday and Friday.

No trains at all will run on the Circle line, Piccadilly line, and in zone 1 on the Metropolitan line and the Central line.

However, TfL stressed that Londoners and visitors would still be able to travel around the city, with other rail lines and transport modes running, and even some tube trains during the two 24-hour strike periods.

The Elizabeth line, London Overground and DLR will run as normal, as well as buses, although increased demand and traffic is likely to slow some services.

Data from the last strikes in April showed that people continued to travel, with patronage across the entire TfL network down only 13-14% overall on most strike days, and approaching normal levels on the Friday.

The bike hire company Lime reported about 20% more trips than average on strike days, while the rival Forest said rush hour hires were up between 35% and 50%.

Tap-ins to the tube were down between 42% and 48% from Tuesday to Thursday but only 31% on Friday, when travel on TfL services was down 6% overall. There is far less commuting on Fridays now but the figures suggest Londoners returned to the tube in the evening for leisure despite some disruption.

TfL said it was not too late for the RMT to withdraw its planned strike action and said the objections the union had raised would be resolved with further, more detailed work. The Aslef union, which represents a slight majority of London Underground drivers, has backed the TfL proposals for a four-day week.

Claire Mann, TfL’s chief operating officer, said: “It is disappointing that the RMT is planning this strike action despite our best efforts to resolve this dispute. We have been clear that our proposals for a four-day week are designed to improve work-life balance and are entirely voluntary.

“A significant number of drivers have indicated that they want us to progress plans for the pilot of this new working pattern on the Bakerloo line, and it would deliver benefits both for our colleagues and our customers. We urge the RMT to work with us so we can resolve this dispute. In the meantime, we are asking customers to check before they travel and allow plenty of extra time for their journeys.”

The RMT union declined to comment.