“据称”的英语可以翻译为：purportedly ...

据称正式会谈仍有可能，但可能性不大。Formal talks are still said to be a possibility, not a probability.他得到了一封据称有首相签名的信。He was given a letter purportedly signed by the Prime Minister.据称，他的货车在那两人过马路时撞上了他们。His van allegedly struck the two as...