Mexico City, Apr 22 (IANS) : The explosion that hit a plant of the Pajaritos Petrochemical Complex in eastern Veracruz state on Wednesday has left at least 13 people dead, the Mexican government said on Thursday.

"We visited the complex's affected areas, and sadly, 13 people have died," wrote Luis Felipe Puente, the national coordinator of civil protection for the Interior Ministry, on his official Twitter account.

On Wednesday night, Pemex and the state government of Veracruz had confirmed an initial death toll of three and 136 others injured, of which 88 remained in hospital in the town of Coatzacoalcos.

Puente said on Twitter that he could not rule out further deaths due to the explosion, as emergency teams could still not enter a part of the plant due to the risk of collapse.

The explosion rocked the Clorados III plant at around 3:15 p.m. on Wednesday, forcing federal and state authorities to evacuate around 2,000 people for a number of hours from residential areas near the complex.

Clorados III is a plant belonging to the Petroquimica Mexicana de Vinilo (PMV) company, a joint venture between Pemex and Mexichem.

Until now, the federal government has not provided any potential causes for the explosion in the plant which produced vinyl chloride.

However, a Mexichem statement on Wednesday night said that air monitoring to detect any toxic substances had ruled out any threat.

Federal police have cordoned off the entire petrochemical complex, and experts began their investigation into the cause of the blast.