MEXICO CITY - Mexico's state oil giant Petroleos Mexicanos (Pemex) Tuesday blamed oil thieves for Sunday's oil pipeline explosion, which killed 28 people and injured 52 others.

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"There was no corrosion, comprehensive maintenance was carried out on the pipeline in 2008," said Juan Jose Suarez Coppel, chief executive officer of Pemex.

"The opening in the pipeline is consistent with a botched illegal tap that triggered a loss of control," he said, adding that illegal tapping of Pemex's pipelines increased to 600 cases this year from 400 of last year.

However, Suarez did not rule out the possibility that some mechanical failure caused the incident.

Carlos Trevino, Pemex's chief financial officer, said Pemex has offered food, clothing, shelter and medical treatment to residents affected by the explosion.

Pemex began to recover the estimated 100,000 liters of spilled crude oil, using a fleet of 19 tanker trucks to ship it to Tula, in nearby state Hidalgo where the company has a refinery.

The explosion took place in San Martin Texmelucan, 90 km east of capital. An official from the Puebla state government, where San Martin Texmelucan is located, told Xinhua by telephone after the explosion that the blast occurred after criminals tapping two oil pipelines running through San Martin Texmelucan lost control of oil flow.