SAN FRANCISCO — Google's share price slid in after-hours trading Thursday as the Internet search giant's first quarter earnings fell slightly short of Wall Street expectations.

Google on Thursday reported a first-quarter net profit on Thursday of $2.3 billion, up from $1.96 billion a year ago, on revenue of $8.58 billion.

Earnings per share of $8.08 came in below the $8.11 forecast by analysts.

Google shares were down 3.77 percent at $554.98 in after-hours trading.

"We had a great quarter with 27 percent year-over-year revenue growth," Google chief financial officer Patrick Pichette said in a statement.

"These results demonstrate the value of search and search ads to our users and customers, as well as the extraordinary potential of areas like display and mobile," Pichette said. "It's clear that our past investments have been crucial to our success today -- which is why we continue to invest for the long-term."

Google said operating expenses were $2.84 billion in the first quarter, or 33 percent of revenue, compared to $1.84 billion in the first quarter of 2010, or 27 percent of revenue.

Google also said it had 26,316 full-time employees as of March 31, up from 24,400 full-time employees as of December 31, 2010.