JERUSALEM, March 17 (Reuters) - Ukrainian Prime Minister Mykola Azarov voiced alarm on Thursday at Palestinian assertions that Israeli agents kidnapped an engineer from Gaza who was visiting his country last month.

Relatives of Dirar Abu Sisi, a manager of the Gaza Strip's main power plant, say he was abducted from a train in Ukraine and is now in Israel. Gaza's Islamist Hamas rulers, who are hostile to the Jewish state, have made similar allegations.

Israeli officials have declined all comment, citing a court-issued gagging order.

I don't want to imagine that such things are carried out on the soil of a friendly state, Azarov said in a newspaper interview published after he wound up a two-day visit to Israel.

We don't have clear information right now. The matter is being investigated by officials responsible for state security. Until we know something for certain, we can't respond, he told Haaretz daily.

Azarov's Israel visit was kept low-key. An invitation to the media to cover his meeting with Prime Minister Benjamin Netanyahu was canceled, and no questions from journalists were allowed at a separate photo-op with Israel's foreign minister.

(Writing by Maayan Lubell; Editing by Jon Hemming)