Ukrainian police said Friday that they are investigating the whereabouts of a Palestinian engineer reportedly kidnapped by Israeli secret agents several weeks ago.

Dirar Abu Sisi, 42, 'disappeared under unknown circumstances' on February 18 while riding a passenger train from the eastern city of Kharkiv to the capital Kiev, the Interior Ministry said in a statement.

His Ukrainian wife, Veronika Abu Sisi, told the German Press Agency dpa that he later telephoned her and said he was being held in a secret Israeli prison.

'Dirar said Israeli secret agents had grabbed him and snuck him out of Ukraine,' she said. 'He has done nothing, and I am absolutely shocked.'

Maksym Butkevych, a spokesman for the United Nations High Commissioner for Refugees in Ukraine, confirmed that Abu Sisi was being detained at a high-security Israeli prison.

He said the engineer's apparently forced removal from the former Soviet republic was 'extremely worrying.'

'We know he was in Ukraine,' Butkevych said. 'He is a registered international refugee, and it is part of our job to keep track of him. What we don't know is how he got from the train to the Israeli prison ... and that's what we're tying to find out.'

On Friday, there was a nationwide ban in Israel on media coverage of the Abu Sisi case. Unconfirmed Ukrainian news reports placed Abu Sisi in a detention centre near the city of Ashkelon.

Veronika Abu Sisi, 32, said she believes Israeli intelligence agents had kidnapped her husband because of his long-standing support of Hamas and his past work at the Gaza Strip's main power plant.

The couple have six children, all of whom are now in Ukraine.

Hamas' Gaza spokesman, Sami Abu Zuhri, blamed Israel for Abu Sisi's disappearance and called for his immediate release.

The interior minister of Gaza's Hamas government has contacted his Ukrainian counterpart and has called for an investigation into Abu Sisi's disappearance, Azbu Zuhri said in a statement.

'We left Palestine precisely to get away from things like this,' Veronika Abu Sisi said. 'I am ashamed for my country.'

She said she reported her husband's disappearance immediately to Ukrainian authorities and that she waited fruitlessly for more than a month for Kiev to push for his return via diplomatic channels.

'There has been no reaction from anyone,' she said. 'All the officials do is tell me to wait.'