WASHINGTON - The Senate called Wednesday for at least 350 miles of new triple-layered fencing on porous sections of the 2,000-mile U.S.-Mexican border to crack down on illegal immigration and smuggling.
The $1 billion proposal, approved by a vote of 83-16, is less extensive than a 700-mile fence proposed by the House of Representatives, but it puts both chambers of Congress in support of building expanded barriers across the southwestern border.

The Mexican government has denounced the House proposal as "shameful," but it didn"t issue an immediate reaction to the Senate proposal, which was approved as an amendment to a comprehensive immigration bill.

Sen. Jeff Sessions, R-Ala., said that his amendment tracks a plan by the Department of Homeland Security to construct fences in areas frequently used by smugglers and illegal immigrants.

The department would determine the locations, but Sessions indicated that much of the fencing would be in Arizona and California and would be linked to a 20-mile fence already constructed near San Diego. The plan also calls for 500 miles of additional vehicle barriers.

Homeland Security Secretary Michael Chertoff has opposed barriers along the full length of the border, but he supports renewed and expanded barriers in vulnerable areas.

The 700-mile fence that the House included in an enforcement-oriented immigration bill in December would cost an estimated $2.2 billion.

Supporters described the Senate plan as a modest alternative to the House one, without the negative symbolism. But Sen. Edward Kennedy, D-Mass., one of the Senate"s leading architects of immigration legislation, lambasted Sessions" explanation that the barriers would be confined to strategic locations.

"Let"s be serious," Kennedy said, contending that the fence could cost as much as $4 billion. "That"s almost a quarter of the whole southern border stretching from California to the Gulf of Mexico."

Inclusion of the fencing appeared to be aimed at making the legislation more acceptable to the House during future negotiations to reconcile differences between the two bills.

President Bush, in an Oval Office address on Monday, urged Congress to pass a comprehensive immigration plan and dispatched political adviser Karl Rove to Capitol Hill on Wednesday in an attempt to shore up House support. Many House conservatives remained adamantly opposed to the Senate bill and said Rove"s visit made little difference.

Senators also voted 66-33 to preserve a key component that would grant legal status to millions of illegal immigrants, but they continued to refine the bill in an attempt to pick up votes from wavering senators in both parties.

Senators unanimously adopted an amendment co-sponsored by Sens. John Cornyn, R-Texas, and Jon Kyl, R-Ariz., that prohibits immigrants convicted of felonies or three misdemeanors from being eligible for the green cards that would give them permanent legal status.

Senators also accepted a Democratic amendment aimed at preventing a temporary guest-worker program from undercutting prevailing wages paid to U.S. workers. Critics of the guest- worker program also have retooled the measure to reduce the total number of guest workers admitted each year to 200,000 from 325,000.