Mexico's President Felipe Calderón has pledged support for the northern city of Ciudad Juárez which has long been the scene of fighting between drugs gangs and the army and police.

Just under two weeks ago, the violence hit an all-time low when armed men stormed a high-school party and shot 15 teenagers dead. The president visited the town in an attempt to ease the situation.

Some critics say his policy of deploying huge numbers of soldiers and police in the city is just making things worse. Hundreds of demonstrators greeted Mr Calderón when he met local officials. There were clashes between dozens of protesters and riot police.