Mexico missing case: Students march in solidarity
Thousands of Mexicans have been marching through the streets of Mexico City to protest against the pace of investigations on the whereabouts of 43 missing student teachers.
They disappeared after clashing with police in the south-western state of Guerrero more than five weeks ago.
University students have begun a 72-hour strike in support of the teachers.
The mayor of Iguala, suspected of involvement in their disappearance, was arrested on Tuesday after a manhunt.
Jose Luis Abarca and his wife were detained without a shot being fired in a house in a working-class neighbourhood of Mexico City.
A woman who had rented the house to the couple was also arrested on suspicion of aiding a fugitive.
The nationwide strike is the latest in a series of protests aimed at putting pressure on the authorities to step up the search for the missing students from a teacher-training college in the town of Ayotzinapa.
Relatives of the missing welcomed Tuesday's arrests.
Prosecutors have accused the mayor of telling the municipal police in Iguala to intercept the students to prevent them from interrupting a speech his wife was giving.
Timeline: Iguala disappearance
26 Sept: Students from a teacher training college in Ayotzinapa travel to Iguala to protest and raise funds
Night of 26 Sept: Police stop the students, 6 people are shot dead, 43 students disappear
30 Sept: Iguala mayor Jose Luis Abarca asks for leave from his post, which is granted
4 Oct: Mass graves are found near Iguala containing 28 bodies
19 Oct: Federal police are deployed to Iguala and replace the municipal force
22 Oct: Mexico's prosecutor general says an arrest warrant has been issued for Mr Abarca, his wife and the town's police chief
23 Oct: Guerrero state governor Angel Aguirre resigns
29 Oct: President Enrique Pena Nieto meets the relatives of the missing students and promises a "renewed search plan"
4 Nov: Mr Abarca and his wife are arrested in Mexico City
Police opened fire on the students, who were in buses travelling back from Iguala to their college, killing three of them and three more people in nearby vehicles.
One busload of students tried to flee, only to be chased down by the municipal officers, who took them to the local police station.
Some of the officers, who have since been arrested, told investigators they then handed the students over to a local drugs gang called Guerreros Unidos (United Warriors).
The leader of the gang, who has also been detained, said that he had been told by one of his men that the 43 were members of a rival gang.
He then reportedly ordered that they be "made to disappear".
A search of the surrounding area has uncovered a number of mass graves containing a total of 38 bodies.
Forensic tests carried out on 28 of the bodies suggested they were not those of the students.
However, Mexico's Attorney General has since said that the initial tests may have been flawed. More tests are currently going on.
The relatives of the missing said they hoped the arrest of Mr Abarca and his wife would yield new clues.
"This was the missing piece. This arrest will help us find our kids," Felipe de la Cruz, told Milenio television.