TUCSON, Ariz. (AP) - U.S. Rep. Gabrielle Giffords said she is circulating a letter to House Speaker Nancy Pelosi demanding that the U.S. House leadership ``do their part to pass comprehensive immigration reform.''

Senators on both sides of the aisle and the White House announced an agreement Thursday on a plan to overhaul immigration to provide millions of illegal immigrants now living in this country legal status and also to fortify the border. The agreement follows weeks of meetings between key senators from both parties and White House emissaries trying to fashion an acceptable measure.

In contrast, ``There has been no movement in the House,'' Giffords, a Democrat from Tucson, said Wednesday. She is a co-sponsor of comprehensive reform legislation authored by Reps. Jeff Flake, R-Ariz., and Luis Gutierrez, D-Ill.

``The consensus is that it needs to pass before August, or we will have lost our window of opportunity for at least 18 months, until after a new president is elected,'' Giffords said.

Senate action on immigration legislation was expected to be taken up before House consideration. Assuming passage of a measure in both chambers, a conference committee would have to reach a compromise resolving any differences.

For several years, Arizona has been the epicenter of illegal immigrant trafficking, and Giffords' southern Arizona district encompasses a sizable segment of the state's border with Mexico.

One of the most important and critical aspects of a reform package, she said, ``is reducing the flow of illegal immigrants to our country.''

She said her top priority is to pass long-overdue comprehensive immigration reform. ``Southern Arizona has been bearing the burden of this failed immigration policy for far too long,'' Giffords said.

Part of the needed reform, she said, includes enhancing border security through more Border Patrol agents, Immigration and Customs Enforcement investigators and port inspectors. In addition, upgraded technology, from using X-ray and radar to sophisticated cameras, unmanned aerial vehicles and more ground sensors, must be part of the mix, she said.

Other key elements include: Employee verification and employer sanctions; granting up to 400,000 temporary worker visas and nearly doubling the number of visas for high-tech workers from 60,000 to 115,000.

Giffords has initiated meetings every two weeks for three months in southern Arizona to involve residents, groups and businesses along Interstate 19 to provide comments and make recommendations concerning construction of a permanent Border Patrol checkpoint along the interstate.

She also wrote Border Patrol Chief David Aguilar this week urging him to address immediately problems resulting from the current placement of a temporary checkpoint along I-19.

She said the placement has resulted in drug and immigrant smugglers detouring through several small communities in the Santa Cruz and Pima counties, endangering local residents while circumventing the checkpoint.

Her letter asked Aguilar to ``make it a priority to move the temporary checkpoint to another location where the impact on residents and businesses can be reduced,'' rather than at its current location just north of Tubac.

``I don't have a specific location of where I think the checkpoint should be located,'' the congresswoman said in an interview.

Calls to a spokesman for Aguilar were not returned immediately.