[Links are to Spanish-language pages except where noted.]
With the deadline for its ultimatum having been reached, the GUPC construction consortium (Grupo Unidos Por el Canal) now says it will not suspend work that could paralyze the project to widen the Panama Canal.  [en]
On Monday, 20 January 2014, time ran out for GUPC's demand that they receive an additional $1.6 billion from the Panama Canal Authority to cover alleged cost overruns. GUPC had threatened a total work stoppage on construction of the third set of locks if, by that date, an agreement was not reached regarding payment.
The Panama Canal Authority has refused both the additional sum and any negotiations outside the terms of the original contract signed with GUPC. The Canal Authority also published a message on its website Mi Canal  [en] in which it clarified that the threat by GUPC is not valid and goes against what is set out in the contract.
GUPC has tried every conceivable means of negotiating outside the contract, but the Canal Authority has refused to look for any way forward that does not strictly abide by the terms of the document. As the consortium includes three European companies, it was suggested that the European Commission mediate the dispute, a possibility that the Canal Authority firmly rejected, insisting the parties respect the provisions of the contract. 
Despite this, GUPC has said it will not suspend work as of January 20,  alleging instead that the ultimatum only sets the date from which the consortium is entitled to order a work stoppage in the event that an agreement has not been reached. However, Canal Administrator Jorge Quijano has reported that construction activity is 30% below normal levels,  risking a potential delay that is unjustified and a breach of the contract.
The unease and lack of transparency on the part of the consortium has upset Panamanians, who consider the Canal part of their national heritage. A group has even organized a protest for Wednesday, February 22.
La protesta ante embajada de España VA! Miércoles 22 al mediodía LLEvar espejitos, bandera Panameña y DIGNIDAD. Basta de chantajes de GUPC!
— Miguel A. Bernal V. (@MiguelABernalV) January 20, 2014 
Protest in front of the Spanish embassy Let's go! Wednesday 22 at noon Bring small mirrors, the Panamanian flag and your PRIDE. Enough with GUPC blackmail!
Twitter user ‘Vía Noticias y Más’ agrees with many Panamanians who trust and hope that the Canal Authority (ACP) will take over construction.
— Vía Noticias y más™ (@Traficologo) January 20, 2014 
It's time the ACP took over the widening of the Panama Canal and got rid of GUPC
For the politician José Blandon, the European companies are trying to pressure Panama into paying more than was agreed to:
No le hagamos el juego a estos señores de GUPC! Ellos saben lo crucial quw es el tiempo para Panama y de allí viene el chantaje
— Jose I Blandon C (@jblandonc) January 20, 2014 
Let's not play into the hands of these gentlemen from GUPC! They know how critical the time is for Panama and that's what accounts for the blackmail
For Rubén Córdoba the way to proceed is to kidnap the team from GUPC and contract another company to finish the work:
@RobertoEisen  La ACP debe remover a GUPC del canal, secuetrarles el equipo y contratar a la empresa Americana/Japonesa por su tec
— Ruben Cordoba (@rubencordoba21) January 20, 2014 
The ACP should remove GUPC from the canal, kidnap the team and hire the American/Japanese company for their tech
Mirla Maria is frustrated and asks that they get rid of the consortium and not let them continue work on the expansion:
— MirlaMaria (@mirlamarian) January 20, 2014 
Why don't they kick out those shameless Spaniards and not let them back in
As long as GUPC's ultimatum hangs overhead, work can be suspended at any time. And although January 20 did not see a complete shutdown, construction is so slow that nobody is discounting the possibility that the Panama Canal Authority will end up taking action on the matter.