German political parties held their final campaign rallies before Sunday's national election, mindful of new warnings by Islamic militants that they would exact retribution for the country's presence in Afghanistan. Two threatening videos surfaced Friday - one by al-Qaida and another by the Taliban - showing video of top German landmarks like the Brandenburg Gate in Berlin and Munich's world-renowned Oktoberfest. On Saturday, authorities banned all flights over Oktoberfest until it ends on Oct. 4. This year's 16-day festival is expected to draw some 6 million visitors. IntelCenter, an organization that monitors terrorism, said the threats directed at Germany are "now at unprecedented levels." Chancellor Angela Merkel hopes to return for a second four-year term and ditch her conservative party's "grand coalition" with her main rivals, the Social Democrats, led by her foreign minister and challenger, Frank-Walter Steinmeier. The 54-year-old Merkel wants to form a new center-right government with her preferred partners, the pro-business Free Democrats. But while she is personally popular among voters - some 49 percent said they would vote for her - Germans vote for parties and do not directly elect candidates. Merkel is widely expected to remain chancellor and her conservatives to be the biggest party. Although Germany's election campaign has centered mainly on how best to spur economic recovery, the role of German troops in Afghanistan has leapt into the spotlight after al-Qaida issued a string of threatening videos aimed at Germans. It's not clear what, if any, affect the terror threats might have on how people vote. None of the main parties advocate an immediate withdrawal from Afghanistan. Only the Left Party has called for that, but it remains a marginal force. "At the moment, I am expecting that the terror alerts will generate no direct reaction of the voters at all, at least no reactions that could lead to a change of voting behavior," said Nils Diederich, political scientist at Berlin's Free University. In an audiotape that surfaced Friday, Osama bin Laden demanded that European countries pull their troops out of Afghanistan and threatened "retaliation" against them for their alliance with the United States in the war. The Interior Ministry on Friday also confirmed the existence of a Taliban video that threatens attacks on Germany. "Your operation here against Islam makes an attack on Germany tempting for us mujahedeen," a German-speaking Taliban fighter in Afghanistan identified as Ajjub says in the video. The Taliban video showed photos of German landmarks, including the Brandenburg Gate in Berlin, Oktoberfest in Munich, the Frankfurt skyline, as well as Defense Minister Franz-Josef Jung and Interior Minister Wolfgang Schaeuble. German authorities tightened security after the first threats, with many more officers now visible at airports and train stations. President Horst Koehler urged Germans go to the polls, recalling that the right to vote was not something to take for granted. "People have died for the free, secret and equal right to vote. It's our democracy and we should not weaken it," Koehler said in a statement Saturday that was to be published in the Sunday newspaper Bild am Sonntag. Germany is the world's second biggest exporter after China, and it has kept its unemployment rate hovering at around 8 percent amid the financial crisis through a series of government-backed short-term contracts. Both Merkel and Steinmeier have ruled out a coalition with the Left, a mix of former East German communists and Social Democrats angered by economic reform.