By Krista Hughes
MEXICO CITY (Reuters) - Mexican President Felipe Calderon on Friday mounted a forceful defense of his crackdown on drug cartels, saying the conflict that has cost thousands of lives was the only way to beat the "cancer" attacking Mexico.
Calderon is under growing pressure to end the violence that has killed more than 42,000 people in less than five years, and he devoted nearly half of his annual state of the nation address to rebuffing critics of his army-backed offensive.
In an impassioned speech a week after 52 people died in an arson attack on a Monterrey casino by suspected drug gang members, Calderon said only by standing up to criminals could Mexico end what he called the "slavery of criminality."
"The only way to really put an end to this cancer is to persevere with this strategy," he said in his address that lasted 1-1/2 hours. "We will defeat them."
"If we had done nothing...the country would be completely dominated by the cartels, crime would have grown to the extent that the institutions of state would have ceased to work, putting them at their disposal," he added.
The surge in violence under his presidency has rattled foreign investors and hurt support for his conservative National Action Party (PAN), which faces an uphill struggle to secure re-election in a presidential vote next July.
Latest polls suggest the main opposition Institutional Revolutionary Party, whose 71 years of authoritarian and often corrupt rule were ended by the PAN's candidate Vicente Fox in 2000, will win the 2012 presidential elections.
Security forces have captured or killed many senior traffickers and Calderon says the violence is a sign of the cartels' weakness. But critics say his policy of using force to bring down the cartels has made a bad situation worse.
Locals in the prosperous northern city of Monterrey were appalled by the death toll after suspected members of the Zetas drug cartel attacked the Casino Royale last Thursday.
Hitmen, local traffickers and police initially made up the bulk of the drug war dead, but most of the largely female victims in the Monterrey casino were middle class, the kind of people who have made the city a PAN stronghold.
Long viewed as a jewel in the crown of the Mexican economy, Monterrey, a city of 4 million, has become a potent symbol of how the drugs war can quickly ravage major cities.
During his speech, Calderon announced plans to give more support to victims of the drug war and said he was ordering a review of all casinos in the country, which analysts say have become targets for extortion by drug gangs.
Calderon, who launched his offensive on the cartels after taking office in December 2006, is barred by law from seeking a second term. His successor will take office in December 2012.
In his address, Calderon warned dozens of the country's top politicians in the audience that any let-up in the fight on the cartels would spell disaster.
"This will not happen, not while we continue to face them with firmness, which my government is completely committed to and will remain so until the last day of my term," he said.
(Additional reporting by Elinor Comlay, writing by Dave Graham; Editing by Vicki Allen)