Google Inc showed strong growth in its ability to convert Web searches into ads viewed, according to a closely watched industry report quoted by analysts on Thursday, and its shares rose 2.5 percent.

Web tracking firm comScore Inc's monthly report on "paid clicks" showed Google's U.S. growth at 19.6 percent in April from a year ago, compared with growth of 2.7 percent in March and 3.1 percent in February, according to analysts.

Lehman Brothers analyst Douglas Anmuth said the growth suggests a reversal in trends seen for Google during the first quarter of the year and could spur shares higher on hopes the Web leader had reaccelerated growth in the market.

"We are cautious about reading too much into the data as they track only domestic (owned and operated) paid clicks and exclude Google's full network and international paid clicks," Anmuth wrote in a note to clients.

Jefferies & Co analyst Youssef Squali said Google could exceed his revenue expectations for the second quarter if growth remained on its current trajectory.

He noted that paid click declines of 4.4 percent for Yahoo Inc and 9 percent for Microsoft Corp's MSN could bolster the case for the two to combine, or for Yahoo to clinch a search partnership with Google that has been under discussion for weeks.

Microsoft withdrew a $47.5 billion bid for Yahoo earlier this month in a disagreement over price. Yahoo Chief Executive Jerry Yang said on Wednesday the two companies were still discussing a potential partnership or alternatives to a deal.

ComScore does not publicly release the paid click reports it sends to clients.

Google shares rose $15 to $583, Yahoo slipped 11 cents to $27.06 while Microsoft gained 32 cents to $28.50.

Source:Reuters