U.S. Democratic presidential contender Sen. Hillary Clinton saw her rating rebound on the eve of Tuesday's pivotal primary in Pennsylvania, according to polls released Monday.

A Zogby International tracking poll of 602 likely primary voters taken April 19-20 shows that Clinton leads her Democratic rival Sen. Barack Obama 48 percent to 42 percent.

In the same poll last weekend Clinton led just 45 percent to 44percent, but she has steadily opened her lead in Zogby's daily tracking since then.

An American Research Group poll of 600 likely primary voters taken April 17-19 shows Clinton leading Obama 54 percent to 41 percent.

A Strategic Vision poll of 1,200 likely Pennsylvania voters taken April 18-20 shows Clinton leading Obama 48 percent to 41 percent.

In general election trial heats, presumptive Republican presidential nominee Sen. John McCain of Arizona tops both Clinton(46 percent to 42 percent) and Obama (48 percent to 40 percent).

The New York Times said although the new polls show Clinton still maintained a lead over Obama, the margin is down from about16-point weeks ago.

It also argued the new "metric" for judging the outcome of the Pennsylvania primary will be the margin of Clinton's victory, and the calculations will begin again on the new measuring grounds of contests in Indiana and North Carolina on May 6.

The New York Daily said many observers believe Clinton has to do decisively well in Pennsylvania to keep party insiders from backing Obama and pushing her out of the contest.

The Democratic race for the party nomination is far from over and neither Clinton nor Obama is likely to get enough delegates going to the national convention to declare victory very soon.

However, as Obama leads Clinton in the delegate count by about 140, she is facing growing pressure to quit the race "for the benefit of the party."

(Xinhua News Agency April 22, 2008)