As the strike by Catholic high school teachers against the Archdiocese of Philadelphia moves into its seventh day, both sides expressed frustration over the slow pace of the talks.

The Association of Catholic Teachers, Local 1776, and negotiators for the archdiocese's Office of Catholic Education resumed talks Monday, but both sides lamented the lack of progress during bargaining Sunday.

The 711 lay instructors who teach at the archdiocese's 17 high schools have been on strike since last Tuesday, when they voted, 589-60, to reject the archdiocese's proposed three-year contract.

The 16,000 students who attend the Catholic high schools in the five-county region will continue to follow a modified schedule through at least Tuesday as administrators and members of religious orders give reading and math tests to freshmen or sophomores.

A spokeswoman for the archdiocese said that no decisions had been made about Wednesday's schedule.

Striking teachers have said they objected to proposed changes in working conditions, and were concerned about job security and the archdiocese's intent to use more part-time instructors.

Union officials said that while their negotiating team had exchanged proposals with the Office of Catholic Education on Sunday, "the major issues that forced us to overwhelmingly reject the archdiocesan proposal and vote to strike remain on the table."

The archdiocese said in a statement that while its negotiators had offered proposals "that addressed the teachers' concerns about job security while maintaining our academic priorities, the association has still not seriously discussed any substantial items regarding educational reform and advancement."

The union Monday night complained that the most recent statement from the archdiocese "grossly distorts the facts." The union said nearly 100 proposals to change the current contract remained on the table.

The sides have been at odds over the archdiocese's desire to overhaul the contract to reflect what it sees as the altered educational landscape of the 21st century, and to give it greater flexibility and control over teaching assignments and scheduling.

In its latest statement, the archdiocese also criticized the union for continuing to press for a salary increase of 14.5 percent over three years. The archdiocese has proposed an average salary increase of 7.84 percent over the same period.

The typical high school teacher earned $50,550 in the last academic year and has been teaching for 20 years, the union said.

Contact staff writer Martha Woodall at 215-854-2789 or martha.woodall@phillynews.com.