ATHENS, Greece (AP) — The captain and chief mechanic of a ship commissioned for an oil-spill cleanup operation outside Athens have been arrested on fuel smuggling charges, further complicating efforts to contain the oil that has polluted the Greek capital's coastline.

The Merchant Marine Ministry said Wednesday that the two were arrested on smuggling charges after undeclared fuel was found on the tanker ship Lassea.

The vessel was being used to recover oil from the wreck of the Agia Zoni II tanker which sank on Sept. 10 while anchored near Greece's main port of Piraeus.

The recovery effort was suspended Tuesday, with a replacement vessel due to be selected Wednesday, ministry officials told the AP.

Oil slicks from the wreck have extended from the island of Salamina near where the sinking occurred, to the entire length of the Athens coast. Local authorities in most of affected areas have issued an indefinite advisory to avoid swimming.

In Parliament Wednesday, opposition parties renewed demands for Merchant Marine Minister Panagiotis Kouroumplis to resign, arguing that his response to the sinking had been delayed and inadequate in the early stages of the containment effort.

Kouroumplis denied the allegations, and told lawmakers: "I assure you that the effort we are undertaking is enormous, perhaps unprecedented in this country. We have heard much criticism, but no suggestions about what should have been done differently."

He said the cleanup effort would last another 30-40 days.

"I believe our response was effective," Kouroumplis said.

The environmental group Greenpeace also strongly criticized the government and its decision to suspend the effort to pump oil out of the sunken tanker.

"If the leadership of the Merchant Marine Ministry has moved heaven and earth, we haven't seen it on the island of Salamina," Greenpeace's Dimitris Ibrahim said.

"Most of its polluted beaches have been abandoned, and the oil spill is still covering a large area."

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