Seattle teachers reached a tentative agreement with the city's school district as their strike enters its fifth day Tuesday, but they will stay on the picket lines pending its approval.

The sides reached a deal, but it must be approved by the Seattle teachers union's executive board and representative assembly before the strike can end, Washington Education Association spokesman Rich Wood said Tuesday morning. No details about the terms of the agreement were immediately released.

"We have a tentative agreement with the district! Go to your picket site this morning to learn more!" the Seattle Education Association told its members in a text message Tuesday.

The sides have been negotiating over issues that include teacher pay, evaluations and the length of the school day. The teachers walked out Sept. 9 and delayed the start of the school year for 53,000 students.

Educators complained that living expenses have become unaffordable as the city's high-paid technology industry booms and they have gone six years without a cost-of-living increase. The district provided raises totaling 8 percent out of local levy money in that time.

The Seattle City Council threw its support behind the striking teachers in the state's largest school district Monday, passing a resolution recognizing the union. The council voted unanimously to designate this week "Seattle Educators Week."

Councilwoman Kshama Sawant said Monday that if the union wins it will be a huge step forward for students and educators, but it would also resonate outside Seattle.

"A victory for the union is also a victory for education across the country. It shows that if we organize and remain united, we can resist attacks on public education," she said.

Meanwhile, Mayor Ed Murray said he met separately with district Superintendent Larry Nyland and union President Jonathan Knapp to offer his help and urge them to reach a fair agreement that would allow the school year to begin as soon as possible.

Pay has been a big sticking point. The union made a counterproposal over the weekend that called for raises totaling 9.75 percent over two years -- far less than the 21 percent over three years they initially sought.

Teacher salaries in Seattle range from about $44,000 to more than $86,000, depending on experience and education.

This year, lawmakers -- facing a court order to increase spending on education -- came up with money for new teachers and supplies. Some $37 million of that money is going to Seattle. The district says it has offered raises totaling 14 percent over three years --  including cost of living adjustments from the state -- but it also wants to extend the school day by 20 minutes, arguing that Seattle has one of the shortest instructional days in the state, at 6 hours and 10 minutes.

The union said the proposal would have forced teachers to work that extra time for free. Over the weekend, the district offered to pay teachers for the added instructional minutes, Howard said. The union proposed studying the pros and cons of an extended school day.

Parents were staying flexible while they waited for a deal. Kim Flanery-Rye had to bring her 7-year-old son to work one day and had his uncle watch him another. Her husband worked from home the third. The city opened 21 community centers around the city to help accommodate up to 3,000 students during the strike.

"This is really a great way to make sure our children are taken care of," said Kim Flanery-Rye, who was relying on care at Miller Community Center this week.