The downgrading of US' credit rating by Standard & Poor’s from 'AAA' to 'AA+' has sent shock waves across America, with many fearing this could affect the financial system worldwide.US Senate Majority Leader Harry Reid said the action by S&P reaffirms the need for a balanced approach to deficit reduction that combines spending cuts with revenue-raising measures like closing taxpayer-funded giveaways to billionaires, oil companies and corporate jet owners.The Wall Street Journal termed it as shaking of the global financial system. It said the downgrade will force traders and investors to reconsider in real time what has been an elemental assumption of modern finance. The journal said, policy makers are also anxious about the hidden icebergs the move could suddenly reveal. It feared that the move could lead to the prompt downgrades of numerous companies and states, driving up their costs for borrowing.The Washington Post said the downgrade will push the global financial markets into unchartered territory after a volatile week fueled by concerns over the European debt crisis and the slowdown in the US economy. It said the downgrade could also have a cascading series of effects on states and localities, including nearly all of those in the Washington metro area.Meanwhile, President Barack Obama has asked leaders of both the Republican and Democratic parties to work together to grow the economy and get Americans back to work.In his weekly address to the nation, Obama said the Congress could take number of measures right now to spur growth and create jobs. The measures include extending tax cuts for working and middle class families, cutting red tape to encourage new businesses to grow, passing trade deals that will support tens of thousands of jobs, and giving out-of-work construction workers opportunities to rebuild the infrastructure.Obama said that in the short term, his urgent mission had to be getting this economy growing faster and creating jobs.Meanwhile, Finance Minister Pranab Mukherjee has described the downgrading as a “grave situation”. Speaking to reporters on the sidelines of a function in New Delhi, he said it had to be analysed.Market regulator Sebi said it was watching the situation closely. Sebi Chairman U K Sinha said everything was perfect and right in our market and there was nothing for the people to worry. He said our risk management system was working perfectly and all the settlements are taking place.