Sarkozy announces French presidential re-election bid

• NEW: Declaration means Sarkozy can throw himself into campaigning for 10 weeks
• NEW: Unemployment and the economy are likely to be big issues on the campaign trail
• Sarkozy is trailing his chief rival, Socialist Francois Hollande, in opinion polls
• The first round of voting is April 22, with a second round May 6

Paris (CNN) -- French President Nicolas Sarkozy officially announced Wednesday that he is running for re-election.

Sarkozy, who heads the center-right UMP party, is currently trailing his chief rival, Socialist candidate Francois Hollande, in opinion polls.

Announcing his candidacy via his newly launched Twitter account, Sarkozy said that not running for a second term would be like abandoning his post.

He said the reforms undertaken by his government were starting to produce results and that he intended to give the French people back their voice by holding referendums.

The first round of voting is scheduled for April 22, with a second round to follow on May 6.

The latest opinion polls suggest Hollande is the favorite in the first round of voting, attracting 30% support to Sarkozy's 26%, according to polling institute IFOP.

Other candidates include Marine Le Pen, of the far-right National Front, and the centrist Francois Bayrou.

The news of Sarkozy's candidacy was expected, but the official announcement means he can now campaign at full tilt for the next 10 weeks.

He is likely to play up higher-than-expected gross domestic product growth of 1.7% for 2011, as he seeks to convince the French people that the economy is in safe hands.

The unemployment rate is likely to be a big issue on the campaign trail, however, at almost 9.3% of the working population.

Sarkozy may also seek to portray himself as someone who has put France at the center of global events during his five-year term in office, using the slogan "A strong France."

Earlier, the French president became the latest high-profile figure to join the social networking site Twitter.

His official account was launched Wednesday morning under the official handle @NicolasSarkozy.

"Hello everyone, I am very pleased to launch my Twitter account today. Thank you to those who will want to follow me!" his welcome tweet read.

Sarkozy's second official tweet urged his followers to watch him being interviewed on French television. "I have accepted the invitation by TF1 to appear on their newscast at 8 p.m. this evening, I hope you will join me."

Eleven hours after posting his first message, he had more than 47,000 followers and was following one other Twitter account, his presidential office -- the Elysee Palace.

In a recent interview with national newspaper Le Figaro, Sarkozy laid out what is likely to be the framework of his campaign.

He told the newspaper he prioritized work and responsibility, and that he would propose two referendums, so he could hear from the French people on imposing tougher rules on immigrants and unemployment benefits.

Asked about his greatest regret in his first term, Sarkozy responded: "When I see all that's left to do and what we have not done...."

Sarkozy was first elected in May 2007.

CNN's Laura Smith-Spark and Jim Bittermann contributed to this report.