President Donald Trump said Tuesday the United States was ready for war against the drug cartels, volunteering American forces to Mexico for the job.

“This is the time for Mexico, with the help of the United States, to wage WAR on the drug cartels and wipe them off the face of the earth,” he wrote on Twitter.

Trump’s remarks were sparked by news of American citizens getting slaughtered in Mexico, after getting caught in the crossfire of a cartel battle in the border state of Sonora. Relatives have said at least nine U.S. citizens were killed including six children of which two were seven-month-old twins, according to CBS News.

Trump urged Mexican President Andrés Manuel López Obrador to ask for his assistance.

“If Mexico needs or requests help in cleaning out these monsters, the United States stands ready, willing and able to get involved and do the job quickly and effectively,” Trump wrote.

The president has campaigned on tackling criminal activity on the border, including the drug cartels. During an exclusive interview with Breitbart News in March, he said he was “very seriously” thinking of designating the drug cartels as foreign terrorist organizations.

“It’s psychological, but it’s also economic,” Trump said at the time. “As terrorists — as terrorist organizations, the answer is yes. They are.”

On Twitter, Trump suggested that Mexico needed American power to wipe out the cartels.

“The great new President of Mexico has made this a big issue, but the cartels have become so large and powerful that you sometimes need an army to defeat an army!” he wrote. “We merely await a call from your great new president!”

A wonderful family and friends from Utah got caught between two vicious drug cartels, who were shooting at each other, with the result being many great American people killed, including young children, and some missing. If Mexico needs or requests help in cleaning out these….. — Donald J. Trump (@realDonaldTrump) November 5, 2019

….monsters, the United States stands ready, willing & able to get involved and do the job quickly and effectively. The great new President of Mexico has made this a big issue, but the cartels have become so large and powerful that you sometimes need an army to defeat an army! — Donald J. Trump (@realDonaldTrump) November 5, 2019