Mexico and Venezuela's presidents, Vicente Fox and Hugo Chavez, are locked in a row, which could have serious consequences for relations between the two nations.
Mr Fox has threatened to cut off all diplomatic ties with Venezuela if Mr Chavez continues making controversial comments about him or his country.
Mr Chavez has refused to apologise for calling the Mexican President a "puppy" of US imperialism.
The BBC News website spoke to readers from both countries to get their reaction to the dispute.
HERNAN VARGAS, 30, ENGINEER, VALENCIA, VENEZUELA
Vicente Fox is clearly conservative and pro-US trade policies, and these policies still reek of failure in Latin America, so it is only fair for presidents in the region to reject them.
What is not acceptable is for President Chavez to drag these political differences down to a personal level.
Mr Chavez should tone down his comments for the sake of Latin-American integration. He is too aggressive towards anyone who supports US policies.
He feels as if he can speak out against the US so vocally because of Venezuela's vast oil resources and the current high price of oil. He should be more reasonable.
I'm sure diplomatic relations between Venezuela and Mexico will be affected by this row and trade will probably be frozen between the two. But this will be fixed once one or both of them are replaced.
President Chavez previously took a similar position with Spain's former Prime Minister Jose Maria Aznar over his support for US foreign policy, but this passed once Mr Aznar left office.
These kind of issues are usually due to personality. They can be treated quite passionately - it is a very Latin American trait. But Mr Chavez is too personal in his comments.
Soon he will start diverting his criticism away from President Fox directly towards President Bush again.
With an election coming up here next year I would like to see someone a bit more diplomatic in power.
Domestically, we also need someone who cares about his own people and is willing to take better care of the poor.
JACINTO DAVILA, 38, LECTURER, MERIDA, VENEZUELA
This is not a quarrel between Mexico and Venezuela.
It is a spat between the presidents, started by Mr Fox who had recently made comments about President Chavez and his policies.
Mr Fox then overreacted to President Chavez's harsh response, which he should have anticipated anyway.
President Chavez may speak more than he should - it is just his way - but he is right. He has to speak for his own people.
The US has been pushing for a Free Trade Area of the Americas (FTAA), with Mexico's support, but we do not want this. We have already had trouble with the North American Free Trade Agreement (Nafta).
The FTAA only serves US interests. We cannot go into a free market economy with the US.
Take agriculture as an example. We cannot compete with America if they keep subsiding their own agriculture.
A different agreement is needed - a more controlled, economic agreement.
As for the current row between President Chavez and President Fox, there will be no major long term consequences.
Mr Fox will probably be gone after next year's elections in Mexico anyway.
On the other hand, President Chavez is likely to win another term in the Venezuelan elections next year.
He is doing what is best for his people and I for one support him.
JUAN PABLO CLINE MARQUEZ, 25, PAINTER, SAN MIGUEL DE ALLENDE, MEXICO
I don't like President Chavez. I have a lot of friends who are from Venezuela and they say he is not governing his people very well.
I was not surprised when he came out and said what he did. It was only a matter of time.
But, at the same time, President Fox should not have spoken out so publicly about President Chavez at the Summit of the Americas.
Unfortunately he started the dispute by doing so. However, this does not excuse Mr Chavez's response.
This row has now escalated out of control.
It will damage relations between the country in the short-term, but not beyond that.
Both countries have lost some of the respect they had for each other, and that will have to be restored in the wake of all this.
For me, it's an emotional issue. I go to Venezuela regularly myself and I feel Mexicans share a lot in common with the people of Venezuela. This will not change because of this.
It is a dispute between two men who are behaving like children and need to look beyond this to see what their countries can do for each other, rather than destroying relations between the two.
However, I think President Fox will come out worse off from this row.
He has already been damaged domestically by the lack of support for him in congress and he has only a year left in office anyway.
The people of Venezuela must decide whether they want Mr Chavez to stay.
MARIO ENCINAS, 50, TEACHER, MEXICO CITY, MEXICO
This is simply an excuse for President Chavez to meddle in Mexican politics.
With Chavez's international and domestic image at a low point at the moment, he took this opportunity to get involved in Mexico's political affairs ahead of next year's presidential election.
There have been suggested links between Mr Chavez and the left-wing candidate Andres Manuel Lopez Obrador.
Although the extent of his involvement has not been documented, I see any interference by Mr Chavez as part of a grand scheme to take Latin America over to the left and create an opposition bloc to counteract the US.
He seeks to criticise anyone who align themselves with the policies of President Bush, and he is doing the same to President Fox.
I feel Fidel Castro is pulling the strings here. He lost any influence he had over the Mexican government when Mr Fox came to office.
The aim now is to polarise opinion against President Fox.
While there is a small pro-Chavez element here in Mexico, most people here feel offended by his harsh words. By insulting the president, he has insulted the Mexican people.
The criticisms of Mr Fox being too close to the US are also wrong. We have had our differences with the US, not least over Iraq.
I don't see relations between the two countries getting any worse than this.
I see both countries keeping their ambassadors out of each other's capitals at least until Mr Fox leaves office.
There will be no free trade agreements in the short term, but in the long term it will be beneficial for Mexico.