PALAWAN - Davao City mayor and presidential candidate Rodrigo Duterte leveled his harshest criticism yet against his rival, Vice-President Jejomar Binay, by comparing the corruption cases against the former Makati mayor to the cases filed against the late dictator Ferdinand Marcos and former First Lady Imelda Marcos.

Speaking in a campaign rally in Puerto Princesa, Duterte lashed out at Binay for saying that the Davao mayor would resort to extra-judicial killings to keep his campaign promise of solving criminality in six months.

"Ang kalaban ko? Binay. Sabi [niya] ako madugo. Bakit ako tatakbo presidente para lang magpadugo-dugo? Ano ito carinderia?" he said, drawing laughter from the crowd gathered to hear him speak.

He then added: "Ikaw [Binay], may kaso ka, corruption. Billion. Hindi lang ikaw, pati asawa mo, pati anak mo. Mabuti pa si Imelda o Ferdinand [Marcos]. Conjugal. Two. Dalawa lang. Eh ito basketball team eh. Eh di ubos."

Duterte's attack signals a change in the tough-talking mayor's rhetoric against Binay, who is one of his rivals in the 2016 presidential race.

During the second PiliPinas debate in Cebu last March 20, Duterte asked Binay if he will withdraw from the race after the Ombudsman found probable cause to file charges against him, his son, former Makati Mayor Junjun Binay, and several others for the overpricing of the Makati City Hall Parking Building II.

Binay, however, said he would not withdraw from the race since he has not been convicted of any crime. The vice-president has denied amassing ill-gotten wealth during his time as Makati mayor.

READ: Duterte twits Binay: Malaki na gastos

During the Puerto Princesa rally, Duterte said he was all set to retire from politics but decided to run because he could not stand the current crop of presidential candidates.

He said that as a former mayor, Binay can talk about fighting drugs and criminality, as well as helping soldiers and policemen.

"But I am talking you as a fellow Filipino, can Binay talk about corruption?" he asked the crowd.

"Hinde!" they shouted.

"Yan ang problema," Duterte added.

'BELOW THE BELT' ATTACKS

Binay's camp, in response, accused Duterte of hitting "below the belt" for including Binay's family members in his attacks.

Binay's spokesperson Atty. Rico Quicho said Duterte should answer his own issues and controversies rather than pick on the family members of the vice-president.

"Ganyan talaga kapag hindi masagot ang mga akusasyon sa kanya, below the belt na ang mga patama," Quicho said.

Binay also expressed disppointment with Duterte for judging him and his family, despite being a lawyer.

He earlier warned the public about the mayor's promise to rid the country of crime in three to six months, saying Duterte would try to accomplish this with his brand of justice in Davao City -- through extrajudicial killings.

Binay called Duterte an "executioner" who only kills poor people.

"Mister berdugo, ako ay pro-life at ang aking ginagawa ay para gumanda ang buhay ng mahihirap. Ikaw naman, pumapatay ka ng mahirap," Binay said.

"Pumapatay ka ng walang pakundangan ng mga bata at magkakapatid. Sanay kang pumatay ng mahirap dahil alam mong hindi sila makakalaban sa iyo. Kaya naman hindi ka pumapatay ng mayaman kasi alam mo lalabanan ka nila," he added.

'BONGBONG SAID MAR NOT A WHARTON GRADUATE'

Duterte, meanwhile, also had harsh words for former DILG chief Mar Roxas, the Liberal Party standard-bearer in the presidential election.

During the rally, Duterte singled out Roxas for doubting his word that he can rid the country of crime in six months.

"Full of promises daw ako. Why? May nagawa ka ba? Panahon ni Cory [Aquino], ni [Joseph] Estrada at [President] Aquino...Show me! Ano ipakita mo sa publiko? Ako meron. Exhibit A: Davao. Punta kayo Davao. Maglakad kayo dun," he said.

The mayor criticized Roxas for his weak performance during his time as transportation and communications chief, adding that the services of the Metro Rail Transit worsened after his watch.

He also described Roxas as "vain," saying that a private plane Roxas is using for his campaign has the registration number 513.

"He is vain, parang babae. Ang lakas ng vanity. Ang registration number [ng plane] is 513. That is his birthday, May 13," he said.

He also revealed that it was Senator and vice-presidential candidate Bongbong Marcos who told him that Roxas is not a Wharton graduate.

"Pa Wharton-wharton ka pa, Watson ka pala," he said.

The Wharton School of the University of Pennsylvania earlier confirmed that Roxas finished his studies at the prestigious business school.

READ: Wharton confirms Roxas is its alumnus

Duterte said electing Roxas as president would mean more of the same system of government, wherein most lawmakers would get a bigger piece of the budget while not allocating enough for Mindanao.

He also reiterated his warning to criminals to change their ways or risk his wrath if he is elected president.

"Gamitin ko military to go out and hunt them and kill them and I will not allow [na] imbestigahan [sila] sa Congress at bababuyin sila, hihiyain sila. Congressman kami dati. Hihiyain tapos magnanakaw din pala. The hypocrisy of it all," he said.

NO APOLOGY TO MEXICO

Meanwhile, Duterte also vowed to improve traffic and infrastructure after he came late to a gathering at the SM Mall of Asia.

The mayor apologized to the crowd for his tardiness, saying his flight in Puerto Princesa was delayed due to air traffic congestion in Manila.

"How can you promote tourism when the traffic is even more horrendous," he said.

During his speech, Duterte also criticized the country of Mexico which is engaged in a war against drug cartels. "Would you enjoy going to Mexico with all the kidnappings and all the killings there?" he asked.

This did not sit well with Mexico's Ambassador to the Philippines Julio Camarena Villaseñor who was also in the crowd.

"Mexico is a very safe country...but just like any other country, we deal with internal issues as well," he said.

Asked if he would apologize to the Mexican ambassador, Duterte said: "Why should I apologize? It's in the newspapers every day."