David Cameron says the government is "doing everything it can" to save thousands of steel jobs - but warned there were "no guarantees of success".
The PM said nationalisation was "not the right answer" after Tata Steel's decision to sell its UK business.
Unions and opposition parties say the government is in "chaos", and want action to save the threatened plants.
Business secretary Sajid Javid has been under pressure as he returns from an official trip to Australia.
Tata Steel's UK business - which directly employs 15,000 workers and supports thousands of others - includes plants in Port Talbot, Rotherham, Corby and Shotton.