A renewed focus on security in recent weeks has boosted the reelection campaign of French President Nicolas Sarkozy, but his opponents are now accusing him of cracking down on potential terrorists for election purposes.

Several factors are working in Mr. Sarkozy's favor. First, there were the shootings in the Toulouse area. A self-proclaimed member of al Qaeda shot three soldiers dead in two separate attacks and raided a Jewish school in Toulouse, killing four people.

Mr. Sarkozy immediately put his campaign on hold, becoming the leader of a grieving nation at a time of frantic soul-searching. Meanwhile, his interior minister blanketed the airwaves, assuring radio and TV audiences that the government was in control. The suspected killer, Mohamed Merah, was himself shot dead by French police on March 22 after a dramatic siege at his Toulouse apartment.

About a week later, TV viewers watched over their morning coffee more scenes of police commandos breaking into the homes of suspected terrorists in a series of dawn raids that led to 17 arrests. And on Wednesday morning, it happened again with 10 more arrests.

To be sure, even prior to the terror attacks in and around Toulouse last month, Mr. Sarkozy was recovering in the polls. But the focus on security allowed him to close the gap with his principal rival, François Hollande, in surveys of the first round. Now, some polls show the incumbent has overtaken his challenger, upping the pressure on Mr. Hollande to increase the momentum of his campaign ahead of the first round of voting on April 22.

But Mr. Sarkozy's political opponents are now accusing the government of leaking the planned raids to television crews.

"Security and staged events are different things," said François Bayrou, a centrist candidate running for president. "Police operations of this sort...should not be done, it seems to me, in the form of a stage-managed advertising campaign."

Representatives of Mr. Sarkozy's campaign couldn't immediately be reached for comment.

Mr. Bayrou did nothing but voice a suspicion that has been on the minds of many observers: if the threat to national security was so pressing, why were the French secret services moving so belatedly? And - more importantly - why so close to the elections?

To be sure, Paris prosecutors said the arrests last week were the culmination of an investigation that began in October. What's more, in the wake of the Toulouse attacks and criticism that French authorities may have allowed Mohamed Merah to slip through their fingers, investigative magistrates are clearly motivated to ensure they are leaving no stone unturned in investigating potential terrorists.

"If there are suspicions, if there are risks, they must be avoided," Mr. Hollande said in a radio interview. "What can be surprising is that it's being done after a terrorist attack that has deeply affected the country."

Still, analysts note that while Mr. Sarkozy has gained in the polls in recent weeks, the move represents a trend that had been underway in any case prior to the Toulouse attacks. Though security is dominating the airwaves with the constant flow of arrests, French people are actually much more focused on the economy, education and unemployment as key elections issues.

A poll conducted after the Toulouse shootings found that concern in France about terrorism had actually fallen to historically low levels.

"It does look like Sarkozy has an instrumental approach to what's happened," said Emiliano Grossman, a politics professor at Paris-based university Science Po. But Mr. Grossman said the president is drawing only a marginal benefit from the campaign's new focus on security.

Despite his advance in the first round, he would still lose to Mr. Hollande in the May 6 run-off, by a wide margin. "The move is too obvious to work well," said Mr. Grossman.