Mittal Steel Co. moved a step closer to the steel industry's biggest takeover after Arcelor SA said it will examine an improved offer from its larger rival.

Arcelor's board, which met yesterday in Luxembourg, will consider the 25.8 billion-euro ($33 billion) proposal, made May 19, once approved by regulators. Arcelor also asked to see a business plan proposed by Mittal's billionaire chairman, Lakshmi Mittal. Mittal's first offer was rejected on Jan. 29, two days after the bid.

Arcelor "didn't say anything negative, which is surprising,"said Michelle Applebaum, an independent analyst based in Highland Park, Illinois, who has covered the steel industry for more than two decades. "They have to take this offer very seriously."

Lakshmi Mittal, 55, last week increased the offer by 34 percent, seeking to create a company that would pour three times more metal than its nearest rival. Arcelor Chief Executive Officer Guy Dolle, 63, has said Arcelor would be better off without the merger because it's expanding outside Europe into lower-cost nations including Brazil.

In addition to the Arcelor board, Mittal has faced opposition from political leaders, including the prime minister of Luxembourg, Jean-Claude Juncker. He said this month he still has "hesitations" about the bid. Luxembourg is Arcelor's biggest shareholder, owning 5.6 percent.

Mittal also added cash and stock and a pledge to cut the family's control over the combined company in the new plan.