Venezuelan President Hugo Chavez led his biggest rally since he was diagnosed with cancer a year ago, seeking to stage a show of strength as he heads register for the upcoming presidential elections, extending his 13 years of socialist rule. Chavez joined tens of thousands of supporters outside the electoral office in the Venezuelan capital, Caracas, in apparent good health. He delivered a nearly three-hour speech with his practiced mix of folkloric spontaneity and militant discourse, marking a dramatic re-entry into the public eye after months of keeping a low profile during cancer treatment. The event was all the more important after his opposition rival, Henrique Capriles, put on a show of youthful vigour on Sunday by leading a 10-km (6.2-mile) march with hundreds of thousands of supporters. \"We have been facing the psychological warfare of the adversary, that Chavez has only a few days left to live, that he is in a wheelchair,\" Chavez told a pulsing crowd after filing his re-election bid with the authorities. \"Now, here I am once again in front of you, registering my candidacy in the name of the fatherland,\" he said, wearing his trademark red beret and track-suit top in the colors of the Venezuelan flag., The speech, which ranged from arcane Venezuelan historical references to casual banter with government ministers, marks the de facto launch of his campaign for the October 7 vote. He has steadily stepped up his public appearances in recent weeks after mostly communicating via Twitter or phone calls to state television. Supporters flooded the streets of downtown Caracas in the hours prior to Chavez\'s appearance, dancing to music pounding from speakers as giant inflatable Chavez dolls waved their arms above the crowd. Hundreds of buses that ferried his followers to Caracas stood parked in side streets. Last year, Chavez, aged 57, had two operations to remove a baseball-sized tumour, and this year had a third operation only months after having declared himself \"cancer free.\" On Sunday, Chavez declared that his latest medical tests showed he is in good health. He did not provide details on his condition or say if he would need more treatment. There has been much controversy around Chavez\'s cancer. Any turn for the worse in his health could mean the end for his movement. That would be a blow to global leftist leaders who see him as an inspiration, but a boon to investors seeking free market reforms in Venezuela and oil companies keen on tapping the world\'s biggest crude reserves.