Germany is set to extend its coronavirus lockdown into a fifth month, a draft proposal shows. The recommendation is being prepared by Chancellor Angela Merkel's office before Monday's video conference of regional and national leaders. At their meeting this month, the leaders agreed on a cautious opening, overriding the objections of Mrs Merkel, who said more infectious variants had made the pandemic hard to control. The Robert Koch Institute for Infectious Diseases said the number of cases for every 100,000 people over a week was 103.9 on Sunday, above the threshold of 100 at which intensive-care units would be completely filled. The draft says the lockdown should continue until April 18 and that an "emergency brake" agreed to at the last meeting will be applied to halt any further lifting of restrictions in areas that exceed 100 cases for every 100,000 people. An earlier proposal circulated by the Social Democrats, junior partners in Mrs Merkel's coalition, that all returning travellers would face quarantine even if they had not been in a coronavirus risk zone was still under discussion in the latest draft. The proposal also mentioned possible evening curfews for areas with high case numbers, although times were not mentioned. The number of confirmed coronavirus cases in Germany has increased by 13,733 to 2,659,516, the institute said on Sunday, and the reported death toll has risen by 99 to 74,664. The latest draft would also increase obligations for companies. Those who were unable to offer their employees the option of working from home would have to provide them with a Covid-19 test each week, or two if supplies were available.