March 29 (Bloomberg) -- The Obama administration plans to give General Motors Corp. enough government aid to restructure over the next 60 days, while Chrysler LLC is being told it must complete a deal with Italian automaker Fiat SpA, according to a government official.

Lawmakers were told on a conference call with administration officials tonight that Fritz Henderson, GM’s chief operating officer, will step in as chief executive officer after CEO Rick Wagoner agreed to the administration’s request that he resign, according to a government official familiar with the briefing.

According to a senior Democratic aide, lawmakers were told this evening that the Obama administration can’t immediately say how much money the automakers will need until they restructure. The aide also said that Chrysler would have 30 days to complete the partnership with Fiat, and that if an agreement is reached the company could receive as much as $6 billion.

GM is surviving on $13.4 billion in U.S. loans and is asking for as much as $16.6 billion in additional aid. Chrysler CEO Robert Nardelli, whose company has received $4 billion and is asking for $5 billion more, hasn’t been asked to resign, people familiar with the talks said.

The officials asked not to be identified before President Barack Obama announces the decision on automaker aid tomorrow.

To contact the reporter on this story: Laura Litvan in Washington at llitvan@bloomberg.net

Last Updated: March 29, 2009 23:20 EDT