Mexico City, Oct 17 (IANS/EFE): The disappearance of 43 students after being led away by police three weeks ago continues to baffle and anger the Mexican public, as well as the government of President Enrique Pena Nieto whose efforts to clear up the matter have been criticised for lack of results.

Pena Nieto said Thursday that the most important task for his government at the moment was to find the students who disappeared in the southern town of Iguala Sep 26 after a night of violence in which six people died.

The government's image first took a hit after it was revealed that several members of the armed forces were involved in the murder of at least eight alleged criminals who clashed with soldiers in Tlatlaya in the state of Mexico.

Right after that incident, the 43 students went missing after they were detained by the police and handed over to the Guerreros Unidos criminal cartel, according to several of those arrested in this case.

On Thursday, a group taking part in the search, reported the discovery of eight graves containing human remains. However, they were not recent enough to be linked to the present case.

With this new discovery, the total number of graves found near Iguala adds up to 17.

The authorities reported that DNA samples taken from the earlier graves did not match those of the missing students.

The federal government increased the number of people participating in the search operations from 900 to 1,200, including a team of divers to search the lakes and rivers in and around Iguala.

Several human rights organisations have said that the case demonstrates the ease with which criminals can make people disappear in Mexico.

According to official figures released Aug 22, there have been 22,322 cases of disappearances in the country since the government launched a war against organised crime in 2006.