LONDON — Iraq’s government must show tangible signs of progress in the next few months, a senior U.S. official said yesterday, citing increased pressure from the American public and the US Congress.The official said the concerns of US lawmakers and the American public were turning up the heat on the Iraqi government to show quickly that it has a national vision for the country that would result in a dramatic reduction in violence.

“The Iraqis have heard a blunt and increasingly sharp message: ‘You have to move ... you have to show us there is an Iraq willing to take the actions necessary to save itself and justify the sacrifice of our money and our young men and young women,” the official said while speaking on condition of anonymity because of the sensitive nature of the situation.

His statements dovetailed with recent remarks by US Defense Secretary Robert Gates, who said the “clock is ticking,” for the Iraqi government to show that it can improve the situation.

The official, speaking to reporters in an interview at the US Embassy in London, said that a September report by Ryan Crocker, the United States’ ambassador to Iraq, and Army Gen. David Petraeus, the senior American commander there, will be critical in offering a benchmark on the state of developments.

“If one looks at when critical progress is to be made, one would be best advised to look at this fall as a key point,” he said.

The official did not speak in detail about precisely what progress must be made, but US lawmakers and other government officials have recently been pressing Iraq’s government to pass a draft oil law that would allow for sharing the country’s vast oil wealth among Sunni, Shiite and Kurdish communities.

The Shiite-dominated government has also been under pressure to review Iraq’s constitution and do more to give Sunni Arabs a say in the country’s future, and thereby hopefully weaken support for the insurgency.

The United States has sent additional troops into Iraq as part of a surge to try to curb violence and create conditions for the government to take decisive steps toward improving its ability to run the country effectively.

Initially, the United States ordered an extra 21,500 combat troops to the country, mainly for Baghdad, but also to be used in Anbar province. An additional 7,000 are going in support positions.

The last of five extra brigades planned in the increase is to arrive by June. There are some 146,000 US troops in Iraq now.

Asked if there could be a hasty US retreat from Iraq, as demanded by many Democrats, the official said that there were no such plans, and that “we still believe progress can be made” in Iraq.

“But while that belief will remain unchanged our ability to move forward to execute the steps necessary to help secure a victory would be very much impacted if there is a loss of American popular and Congressional support,” he said.

“We are pressing them politically to move by underscoring as bluntly, as explicitly as we can ... that the clock is ticking, the patience of the American people is not unlimited, you have got to move,” he said.