Yahoo secretly scanned millions of its users' email accounts on behalf of the US government, according to a report.
据一份报告显示，雅虎曾协助美国政府对其数百万用户的邮件进行了扫描。
Reuters news agency says the firm built special software last year to comply with a classified request.
据路透社表示，雅虎去年开发了一款特殊软件来满足分类要求。
"Yahoo is a law abiding company, and complies with the laws of the United States," the tech firm said in a statement provided to the BBC.
雅虎公司在一份提供给BBC的声明中说道：“雅虎是一家守法公司，遵守美国的法律。”
The allegation comes less than a fortnight after Yahoo said hackers had stolen data about many of its users.
在这起指控之前不到两周的时候，雅虎曾经宣称黑客窃取了该公司许多用户的数据。
Yahoo is in the process of being taken over by Verizon Communications in a $4.8bn (3.8bn pound) deal. The telecoms provider declined to comment on the report.
雅虎正在被威瑞森通讯公司收购的过程中，据悉该公司以48亿美元（约合38亿英镑）的价格收购了雅虎。威瑞森通讯公司拒绝就这份报告发表评论。

Reuters reports that the scans were requested by either the National Security Agency (NSA) or the FBI, according to three sources - two of whom it says were ex-Yahoo employees.
据路透社报道，三名知情人士（其中两人以前是雅虎的员工）透露称，扫描邮件是受美国国家安全局或者联邦调查局的要求。
The news agency says that the software scanned for a string of characters within all incoming emails, but adds that it was unable to determine what information was handed over or if other internet companies had received a similar demand.
路透社表示，这款软件在所有载入的邮件里检索了一个字符串，但是该社也表示无法确定雅虎到底移交了什么信息，也不能确定其他互联网公司是否也收到了类似的要求。
US law allows the country's intelligence agencies to order the release of customer data that they believe could prevent a terrorist attack, among other reasons.
美国法律允许该国情报机构在认为可以防止恐怖袭击或者其他原因的情况之下，命令企业公布客户的数据。
Companies can challenge such orders behind closed doors in the Foreign Intelligence Surveillance Court.
在“外国情报监控法庭”上，企业可以对这些命令提起反对。
But Reuters reports that Yahoo decided not to fight the matter because it thought it would lose. It adds that some Yahoo employees were upset by that decision.
但是据路透社报道，雅虎决定不反对这件事，因为它知道自己一定会输。据悉，当时雅虎一些员工对这一决定感到非常失望。
The whistleblower Edward Snowden, who previously revealed details about the US's cyber-spying efforts, has tweeted in response to the unverified allegations: "Use @Yahoo? They secretly scanned everything you ever wrote... close your account today."
斯诺登是此次雅虎事件告密人之一，他之前曾经公布过关于美国从事网络间谍活动的详细信息，他在推特上回应这起尚未被证实的指控说：“还在用雅虎？他们偷偷地扫描了你写的所有东西，马上注销账号吧！”