Chinese police Wednesday blocked access to a school that collapsed in last month's massive earthquake, a day after breaking up a protest by parents of students who died in the disaster. A cordon of police held back reporters and others gathered at Juyuan Middle School on the edge of Dujiangyan in Sichuan province. More than 270 students died when the school collapsed in the May 12 earthquake. On Tuesday, police broke up a group of parents protesting outside a Dujiangyan courthouse over the loss of their children. The police action was the sternest response so far by authorities toward dozens of grieving parents who had been holding impromptu gatherings and memorial services to vent their anger.

The students' deaths have become the focus for Chinese, both inside and outside the quake zone, fueling accusations about corruption in school construction.

Thousands of students were killed in the earthquake, in which the confirmed death toll has passed 69,100. Angry parents and even rescuers have pointed to steel rods in broken concrete slabs that were thinner than a ball point pen among the 7,000 classrooms that were destroyed.

"Oh, my child!" one woman wailed as officers took the arms of the Juyuan school parents gathered outside the courthouse Tuesday.

"Tell us something!" other parents shouted as police led them away.

Surrounded by police at a side entrance to the courthouse, the parents tried to present what some described as a lawsuit, saying they had no other option because local officials were not responding.

The papers were refused, the parents said, and calls to local police were not answered.

The government has taken some steps to try to help grieving parents. On Tuesday, Beijing began giving compensation to some families whose children died in the quake - about $144 per year to each parent who lost an only child. The Ministry of Civil Affairs also announced that parents who had lost their only child had first priority in adopting children orphaned by the disaster.

Suspicions between the government and grieving parents have grown since the quake, although the Chinese government had been generally praised for its response, including the freedoms allowed both to foreign and domestic media.

In Beijing, Foreign Ministry spokesman Qin Gang said the "principle of transparency and openness remains unchanged." However, he also said local authorities were making decisions based on the conditions in the disaster zone, though "they are not trying to block any news or make difficulties for the reporters."

Meanwhile, the official Xinhua News Agency reported Wednesday that there is still no sign of a helicopter that crashed Saturday while ferrying earthquake survivors. Thousands of soldiers have combed remote mountains in search of the military helicopter.

The Russian-designed Mi-171 transport was carrying at least 14 people - including four crew and 10 survivors - when it flew into fog and turbulence and crashed near the epicenter of the quake in the town of Wenchuan, Xinhua said.