Google posted a 30 percent increase in its first quarter profit, exceeding the forecasts that had cited concerns of the weak U.S. economy and a decline in advertising spending.

The results pushed Google's stock up by 18 percent.

The Internet giant reported a gain of $1.31 billion or $4.12 per share during the first three months of the year compared with $1 billion or $3.18 per share last year during the same period.

The figures released by the firm surpassed the forecasted $4.52 per share.

It's clear we are well positioned for 2008 and beyond, regardless of the business environment we are surrounded by, said Eric Schmidt, Google Chief Executive.

Google's report revealed that its Internet's advertising market is still strong within and outside the United States although the international markets accounted for more than half of Google's revenue.

The first quarter revenue was $5.19 billion, 42 percent higher than $3.66 billion last year.

Google's first quarter net revenue was $3.7 billion, 100 million higher than the forecasts.

Google shares increased by 17.7 percent or $79.64, on Thursday boosted by the results.