Ciudad Juárez (Mexico) (AFP) – Mexico’s top presidential candidates launched their campaigns Sunday vowing to take a harder line against Donald Trump, with the leftist front-runner vowing his country is done being the US president’s “pinata.”

Just as candidates were putting the finishing touches on their opening campaign speeches for Mexico’s July 1 elections, Trump crashed the kick-off party via Twitter, accusing the country of doing “very little” to stop illegal migration and drugs, and renewing his threat to axe the North American Free Trade Agreement (NAFTA).

The veteran leftist leading in the polls, Andres Manuel Lopez Obrador, and his conservative rival, Ricardo Anaya, both hit back hard at the Republican president, whose anti-Mexican diatribes and insistence that Mexico pay for his planned border wall have made him supremely unpopular here.

“We are going to be very respectful toward the United States government, but we are also going to demand that (the United States) respect Mexicans,” Lopez Obrador told a cheering crowd in Ciudad Juarez, on the US border.

“Neither Mexico nor its people will be the pinata of any foreign government.”

Lopez Obrador, a former Mexico City mayor, repeated his long-standing criticism of Trump’s planned border wall.

“Let this be heard near and far: neither security issues nor social problems can be resolved with walls,” he said, condemning Trump’s “mistaken foreign policy” and “contemptuous attitude toward Mexicans.”

Anaya, who is locked in a brutal battle for second place with ruling party candidate Jose Antonio Meade, vowed to answer Trump with a “strong and dignified stance,” and defied the US president to take action on security issues on his own side of the border.

“Just as the United States is worried about undocumented migrants, Mexico is worried about gun trafficking,” he said.

“Eighty percent of the guns used to kill people in our country come from the United States,” he added, in reference to a wave of drug cartel-fueled violence that has left more than 200,000 people dead in Mexico since 2006.

– Migrant caravan –

Trump’s Twitter comments were an apparent response to news reports about a caravan of hundreds of people, including Central Americans, who are heading toward the US border in what they are calling a “migrant viacrucis” (“way of the cross”).

On Sunday, “Fox and Friends,” one of Trump’s favorite TV shows, highlighted the caravan on Twitter, possibly drawing the president’s attention.

“Mexico is doing very little, if not NOTHING, at stopping people from flowing into Mexico through their Southern Border, and then into the U.S.,” he wrote.

“They must stop the big drug and people flows, or I will stop their cash cow, NAFTA. NEED WALL!”

Mexico sends some 80 percent of its exports to the United States under NAFTA, which also includes Canada. Trump calls it the worst trade deal ever signed.

Mexican Foreign Minister Luis Videgaray also reacted defensively, saying Trump’s tweets were based on an “inaccurate news report.”

– Crime, corruption –

Lopez Obrador, who is making his third bid for the presidency, has emerged as the man to beat in the race to succeed Mexico’s deeply unpopular President Enrique Pena Nieto.

Recent polls for the single-round election give him just over 40 percent of the vote, with Anaya and Meade in the 20s.

Criticized for what opponents call a radical and intolerant side, Lopez Obrador has sought to steer clear of controversy this time around and soothe fears that he would wreck Latin America’s second-largest economy.

Lopez Obrador, 64, said in his opening speech that his major reform would be “a government that will no longer serve a greedy minority.”

Meade, 49, also hammered home on the political corruption that has long dogged Mexico, trying to distance himself from the scandals that have stained Pena Nieto and the ruling Institutional Revolutionary Party (PRI) — which chose the respected former finance minister as its candidate even though he is not a party member.

“Mexicans are fed up with corruption. I will be relentless in fighting it,” he told a rally in Merida, on the Yucatan peninsula.

Anaya, 39, meanwhile homed in on the brutally violent crime plaguing the country.

“Our number one priority will be to restore peace and tranquility,” he said.