A spokesman for the speaker of the Palestinian parliament arrested by Israel says he has been hospitalized after being beaten.
But an Israeli army spokesman says Abdel Aziz Duaik underwent tests at a hospital in Jerusalem after complaining of dizziness and chest pains.
Duaik was one of two officials from the governing Palestinian militant group Hamas arrested by Israel on Sunday. Israel describes Duaik as a leader of a terrorist group.
Hamas' charter calls for Israel's destruction.
Meanwhile, Palestinian officials are investigating a suspicious letter addressed to Prime Minister Ismail Haniyeh that sickened seven people. They say the people required medical care after opening the letter at Mr. Haniyeh's West Bank offices.
Officials say the letter had a Tel Aviv postmark.
Mr. Haniyeh lives in Gaza and is banned by Israel from traveling to the West Bank.
Israel has detained more than 30 Hamas officials since Palestinian militants killed two Israeli soldiers and kidnapped a third in June. Israel's military says its offensive in the Gaza Strip will continue until the kidnapped soldier is freed.