HONG KONG — The mysterious Chinese oil company known as CEFC China raised eyebrows wherever it went. Its executives hinted at deep connections within Beijing’s halls of power as well as with China’s powerful military.



Then, last year, prosecutors in the United States arrested one of its top executives, accusing him of bribery in an effort to secure oil rights in Chad and Uganda. Now, they say, he also explored businesses beyond oil: brokering arms deals in other countries and looking for ways to dodge American sanctions on Iran.

In a filing on Tuesday in a federal court in New York, prosecutors said that the executive, a former Hong Kong city official and ophthalmologist named Patrick Ho, had discussed using the company’s connections to help sell weapons to Chad, Qatar and Libya. The prosecutors also accused Mr. Ho of exploring whether CEFC could serve as a middleman for an Iranian company to gain access to funds from a Chinese bank under international sanctions.

Edward Kim, a lawyer for Mr. Ho, declined to comment on Wednesday. CEFC did not respond to a request for comment. Federal prosecutors did not say whether any of these deals went through and did not press additional charges.

But the allegations add a new dimension to what is currently known about CEFC. Virtually unknown just a year ago, it leapt onto the global stage when it said it would buy a $9 billion stake in Rosneft, the state-controlled Russian oil giant.