President Barack Obama's hopes for sweeping reforms to the US health care system appeared in serious danger as he called top Democratic leaders to the White House on Friday, dpa reported. Obama summoned Senator Harry Reid, the Senate's top Democrat, to the White House a day after Reid declared that an August deadline for his chamber to pass an initial health reform bill would not be met. Reid's announcement marked a serious setback for Obama's call for his signature piece of domestic legislation to be approved by the end of the year. Lawmakers in both houses of Congress have been deadlocked over the past few weeks, unable to bridge gaps over the cost of the reforms. Republicans and some Democrats have balked at the price tag for reforming a system that is already the most expensive in the developed world. Obama on Thursday played down the delay, insisting that reaching a deal was more important than its speed. But he invited both Reid and Senator Max Bauchus, who chairs the Senate's powerful finance committee, for a closed-door meeting at the White House on Friday.