GUWAHATI, Dec 28 ? ULFA chairman Arabinda Rajkhowa has appealed to the People's Republic of China to offer safe passage to the ultras for temporary shelter in that country, reports PTI. Rajkhowa, in a letter faxed to the ?Chairman of the Peoples Republic of China? on December 25, copies of which were e-mailed to a section of the local media here today, said that of late ?we have come under massive attack of Indo-Bhutan joint forces and our combatants have been forced to retreat up to Sino-Bhutan border due to all-out air and artillery campaigns?. Rajkhowa said that at this moment ?they have no option but to enter the territory of China to save their lives as they are negotiating with sub-zero temperature and starvation without any clothes and foodgrains. We request you to permit them safe passage to your territory with minimum temporary hospitality necessary for their survival?.