Democratic frontrunner John Kerry kept his big leads in Missouri and Arizona and closed the gap on Wesley Clark in Oklahoma three days before a crucial round of seven Democratic presidential contests, according to a Reuters/MSNBC/Zogby poll released yesterday. Kerry sought yesterday to lock up the presidential nomination in next Tuesday's clutch of primary votes amid newly released campaign finance data likely to fuel attacks from his rivals. John Edwards, needing a win in South Carolina to keep his campaign alive, widened his lead over Kerry in the state to four points in the latest three-day tracking poll. Kerry, after back-to-back wins in the first two contests, holds a 33-point lead in Missouri and a 16-point lead in Arizona, where Clark shaved five points off his advantage in one day. In Oklahoma, Kerry gained five points on Clark to trail 25 per cent to 22pc. Hoping to cement his front-runner status, Kerry was campaigning in the midwestern US state of Missouri yesterday, armed with fresh labour backing but increasingly the target of rivals. Howard Dean, his own campaign jolted by stunning early losses and sagging polls, stepped up his criticism of Kerry, arguing that the Massachusetts senator's public record is lacking in accomplishments. Voter surveys showed the veteran Massachusetts senator, buoyed by stunning wins in Iowa and New Hampshire, with commanding leads in three states holding more than half of the 269 delegates at stake and running strong elsewhere. Those attacks were likely to be fuelled by reports Kerry - has made a fight against corporate special interests a centrepiece of his campaign - has taken more money from paid lobbyists than any other senator in the past 15 years. The Washington Post, citing finance reports filed with the government, said Kerry has raised nearly 640,000 US dollar from lobbyists, including more than 225,000 US dollar for his presidential race - more than twice that of his nearest Democratic rival, Senator John Edwards. A spokeswoman for Kerry told the Post the money had no effect on his Senate votes. But rivals, including early favourite turned fading star Howard Dean and former Nato military commander Wesley Clark seized on the information as a means to dent Kerry's support. Clark has been running television advertisements highlighting Kerry's ties to special interests with the slogan: "Do we really need another Washington politician?" A spokesman for Dean sounded a similar theme. "Kerry has been withdrawing money from the special interest bank for his entire career and now - because it's the popular thing to do - he wants us to believe that he's going to close the account and go after the people that have funded his political career," Jay Carson, spokesman for former Vermont governor, told the Post. **PHOTO CAPTION*** Democratic presidential hopeful Sen. John Kerry, D-Mass., gestures during a rally at the Oklahoma Firefighter's Museum in Oklahoma City, Saturday Jan. 31, 2004. (AP Photo/Charles Krupa)