DALLAS -- Thousands of students from four Dallas high schools walked out of Monday morning classes and gathered at Kiest Park and Dallas City Hall to rally for the rights of illegal immigrants.

School officials estimated that 4,000 students -- most from Skyline, North Dallas, Townview and Molina high schools -- participated in the walkouts and demonstrations.

According to Dallas Independent School District spokesman Donald Claxton, the students from Skyline marched to Dallas City Hall, while the others went to Kiest Park in Oak Cliff.

Dallas police blocked off traffic in and around Kiest Park as students flooded the streets.

Chopper 5 showed several Dallas police officers at the park.

Some students in Garland also walked out from classes at Lakeview Centennial High School. A spokesperson said about 70 to 75 students peacefully gathered in front of the school at 8 a.m. before returning to class two hours later.

About 1,500 people marched in downtown Dallas on Saturday. At a dinner meeting of the Latino group LULAC, leaders announced a major rally on April 9.

"We are going to be having, hopefully it will be the largest civil rights demonstration in the history of Dallas, Texas -- 100,000-plus," said LULAC representative Domingo Garcia.

Dallas school officials said the students who participated in the rallies would receive an unexcused absence.