Prime Minister David Cameron visited the Tata Steel works at Port Talbot in south Wales to assure workers, unions and bosses of the Government's commitment to support the future of steel-making at the under-threat plant.
Unions welcomed the recent offer of state support for potential buyers of Tata Steel's loss-making UK assets, but stressed that any action must cover plants across the whole country and not just in Wales.
The general secretary of the Community union, Roy Rickhuss, said the Prime Minister had "looked proud steelworkers in the eye and promised to do all he could to protect their jobs", and said his union would "hold him at his word".
The PM's surprise visit came as a director at the plant seeks to put together a management buyout of the firm's UK business, which was put up for sale last month.
Mr Cameron was joined by Wales Secretary Alun Cairns for a tour of the plant, which employs more than 4,000 workers. But Business Secretary Sajid Javid - who earlier this month flew to India for talks with Tata's Mumbai-based bosses - was not present.
Downing Street said that the PM and Welsh Secretary spoke to workers in the Port Talbot blast furnace control room and finishing lines before holding round-table discussions with unions and managers, including the chief executive of Tata Steel Europe Hans Fischer.
Mr Cameron's official spokeswoman said that talks focused on "the action the Government has taken to support the steel industry", adding: "The Prime Minister underlined our commitment to working with Tata to support the future of steel-making in Port Talbot and emphasised the need for the Tata sales process to cover the whole business and for there to be sufficient time for that process to run.
"The Prime Minister has been clear throughout that the Government should do all it can to support the sustainable future of steel-making in Port Talbot."
The PM's spokeswoman said it was his first visit to the plant, though other ministers, including Mr Javid, had visited on a number of occasions and Mr Cameron had been involved in top-level discussions ever since Tata announced its decision to sell.
Mr Rickhuss, who was joined by union representatives from Port Talbot and Llanwern, said: "David Cameron has now joined the growing list of senior politicians who have visited Port Talbot, but today we made it clear that steelworks throughout England and Wales are also under threat. This is a national industrial crisis and the Prime Minister needs to act nationally, and indeed globally, to secure a sustainable future for the UK steel industry.
"Steelworkers will now be watching and waiting for the Prime Minister to match his words with real action. We need immediate action to save the industry but also a long-term plan to give UK steel-making a fair chance to compete.
"The Prime Minister has now seen first-hand the great blast furnaces of Port Talbot, both of which will be vital to any future success of the business. He looked proud steelworkers in the eye and promised to do all he could to protect their jobs. Our Save Our Steel campaign will continue as we hold him to his word."
Dai Bowyer, steelworker and Unite executive committee member, described the meeting as "constructive" and said unions had urged the PM to ensure that UK steelworkers have "a level playing field on which to compete with our global competitors", including by tackling energy costs and the dumping of cheap Chinese steel, as well as help with high business rates.
"During the conversation we welcomed the recent commitment by his Government to take a public stake in the UK steel industry, stressing the importance of steel to Britain's manufacturing base," said Mr Bowyer. "Clearly impressed by what he saw, we trust that David Cameron will keep his word in doing everything he can to support steel in Port Talbot and the rest of the UK."