(February 3, 2004) - (Little Rock-AP) -- Pulaski County School District officials have an ultimatum for striking school bus drivers: return to work or else. Superintendent Don Henderson says any drivers who do not return to work by Friday will be fired. The strike is in its second week. The job action is being taken by a union representing about 300 bus drivers. Henderson says several more drivers crossed picket lines to return to their jobs yesterday. Of about 350 buses that would normally run, 133 buses were on the road yesterday -- up 90 from Friday. Of the district's 18-thousand,477 students, three-thousand,462 were absent yesterday, according to figures provided by the district. That means about 81 percent of the students were in school. After a weekend of meetings, the striking bus drivers say they plan to remain on picket lines and are asking for help in their confrontation with the district.