German Foreign Minister Guido Westerwelle is to visit Sudan on Thursday, catching up on a visit that was cancelled last week because of plume of volcanic ash, dpa cited Berlin aides as saying. After talks in Khartoum, he would visit the province of Darfur and then the south of the country, which is set to secede next month, the aides said Wednesday. He would return Friday to Berlin. South Sudan becomes an independent nation on July 9. Last week's visit was called off when an eruption in Eritrea made aviation in the area unsafe.