About 20 members of a group planning to march on Tuesday outside the Xcel Energy Center during the Republican National Convention set up an encampment on St. Paul's Harriet Island on Thursday. Hundreds could be staying there next week, according to the Poor People's Economic Human Rights Campaign. Late Thursday, St. Paul police, enforcing the ban on overnight camping in city parks, arrested two protesters and persuaded the rest to leave, said Peter Cooper, the campaign's press coordinator. The protesters planned to reconvene this morning, Cooper said.