Kevin Rudd resignation sparks leadership ballot rumours Kevin Rudd has been accused of undermining Julia Gillard's government in order to regain leadership. Australia's foreign minister, Kevin Rudd, has resigned, clearing the way for him to mount a challenge for the leadership of the Labor party against Julia Gillard, the woman who replaced him as prime minister. In response, Gillard said she would hold a conference on Thursday, leading to speculation that she will announce a leadership ballot. Rudd made his announcement in the middle of the night in Washington, where he was on an official visit. It came after months of speculation that he would make a move to try to replace Gillard. "I can only serve as foreign minister if I have the confidence of Prime Minister Gillard and her senior ministers," Rudd said. He then blamed senior ministers for attacking his integrity, and Gillard for not doing anything to counter them. "I can only reluctantly conclude that she therefore shares these views," he said. Gillard replaced Rudd as prime minister in June 2010 in an internal coup, and their centre-left Labor party won elections later that year to lead a minority government. Gillard responded to his statement, saying: "I am disappointed that the concerns Mr Rudd has publicly expressed this evening were never personally raised with me, nor did he contact me to discuss his resignation prior to his decision." Speculation about a leadership challenge has been going on for months. At its heart is Gillard's dismal showing in opinion polls. On current trends, Labor faces being wiped out at the next election due in 2013, with its support stagnant at about 30%. Labor party strategist and Rudd loyalist Bruce Hawker, said Rudd is the most popular politician in the country and the best-placed person to win the next election. He's got runs on the board and I think the Australian public think he was done a very bad deal in the way in which he was removed (as prime minister). Now there could be an opportunity to address some of that," he told ABC television. In June 2010, Gillard mounted a surprise attack on Rudd. He resigned as prime minister in a matter of hours without a ballot taking place. Questions about her legitimacy have dogged her ever since and Rudd routinely outperforms Gillard as preferred leader in polling. On Wednesday, ministers accused him of undermining the government in a bid to regain the leadership. "I'm glad that it's now been resolved," said Tony Burke, sustainability and environment minister. "Everybody has had enough of the stealth and undermining campaign that has been going on," he told ABC TV. The battle for the leadership intensified last weekend when a video was released showing Rudd swearing while he was prime minister. Calls from senior cabinet ministers for him to go followed shortly after. Rudd said he will return to Australia on Friday to consult with his family and colleagues about his next move. He's expected to make a statement before parliament resumes on Monday. His options include returning to the backbenches; resigning as an MP (forcing a byelection in a hung parliament with a wafer thin majority) or; if he can gather the required numbers within the party, mounting a challenge for the leadership.