The circumstances are still sketchy, but the Zapatista Army of National Liberation (EZLN) in Chiapas, Mexico, has announced it is going on "red alert". This account from VOA, June 21:

Mexico's Zapatista rebel group has declared a state of emergency, putting its troops on alert and sending its leadership into hiding. In a statement issued Monday, the Zapatistas said they are calling all troops back to their bases and are evacuating their leadership to ensure their safety. The group says its leadership will do its work clandestinely for an indefinite period of time. The group also shut down its radio station. Civil rights activists say the declaration was likely prompted by some action by the Mexican army...

Here is an English translation of the EZLN's communique, from IMC Chiapas:

Communiqué from the Clandestine Revolutionary Indigenous Committee — General Command of the Zapatista Army of National Liberation.

Mexico.

June 19, 2005

To the People of Mexico:
To the Peoples of the World:

Brothers and Sisters:

As of today, the Zapatista Army of National Liberation has declared, throughout all rebel territory, a

GENERAL RED ALERT

Based on this, we are informing you:

First - That at this time the closure is being carried out of the Caracoles and the Good Government Offices which are located in the zapatista communities of Oventik, La Realidad, Morelia and Roberto Barrios, as well as all the headquarters of the authorities of the different Rebel Zapatista Autonomous Municipalities.

Second - That also being carried out is the evacuation of the members of the different Good Government Juntas and the autonomous authorities, in order to place them in shelter. Now, and for an indefinite time period, they will be carrying out their work in a clandestine and nomadic manner. Both the projects as well as the autonomous government will continue functioning, although under different circumstances than they have been up until now.

Third - That basic community health services will continue functioning in the different Caracoles. Civilians will be in charge of these services, and the CCRI-CG of the EZLN is distancing them from any of our future actions, and we are demanding that they be treated as civilians and with respect for their life, liberty and goods by government forces.

Fourth - That there has been a call-up of all members of our EZLN who have been engaged in social work in the zapatista communities and those of our regular troops who have been in their barracks. In a similar fashion, all broadcasts by Radio Insurgente, "The Voice of Those Without Voice", in FM and in short wave, have been suspended for an indefinite period of time.

Fifth - That, simultaneous with the publication of this communiqué, national and international civil societies who are working in peace camps and in community projects are being urged to leave rebel territory. Or, if they decide freely of their own volition, they remain on their own and at their own risk, gathered in the caracoles. In the case of minors, their departure is obligatory.

Sixth - That the EZLN announces the closing of the Zapatista Information Centre (CIZ), not without first thanking the civil societies who have participated in it, from the time of its creation until today. The CCRI-CG of the EZLN formally releases these persons from any responsibility for the future actions of the EZLN.

Seventh - That the EZLN releases from responsibility for any of our future actions all persons and civil, political, cultural, citizens and non-governmental organizations, solidarity committees and support groups who have been close to us since 1994. We thank all of those who have, sincerely and honestly, throughout these almost 12 years, supported the civil and peaceful struggle of the zapatista indigenous for the constitutional recognition of indigenous rights and culture.

Democracy!
Liberty!
Justice!

From the Mountains of the Mexican Southeast.
By the Clandestine Revolutionary Indigenous Committee — General Command of the Zapatista Army of National Liberation.

Subcomandante Insurgente Marcos

Mexico, in the sixth month of the year 2005.

NOTE: The "Caracoles" (snails) are the regional seats of the Zapatistas' civilian governing bodies, the Good Government Juntas.

If anybody has more information, please post it below.