The Cairo bureau chief of TV channel al-Jazeera has been charged with false reporting and released on bail after more than a day in custody.
The triple bombings in Dahab killed at least 18 people
Police had questioned Hussein Abdel Ghani over his coverage of the Sinai bombs earlier this week.
The interior ministry said the journalist had falsely reported a blast in eastern Sharkia province.
"I'm fine but I have had hardly any sleep for the past 40 hours," the reporter told al-Jazeera by phone.
He was released on bail of 10,000 Egyptian pounds or $1,745 and charged with "propagating false news that can disturb national security and cause chaos", according to al-Jazeera.
A triple bombing of the Sinai resort of Dahab on Monday killed 18 people.
On Wednesday, two suicide bombers attacked security personnel and foreign peacekeepers at el-Gorah in the Sinai Peninsula, but did not cause any injuries.
The interior ministry said Mr Abdel Ghani's arrest concerned the false reporting of an explosion in Sharkia on Wednesday.
The reporter has denied the charges against him
A spokesman said: "[Hussein Abdel Ghani] said there were incidents in Sharkia and nothing happened. He's spreading confusion.
"When he said there was an explosion in Sharkia, leading everyone to ask about it, about something that didn't happen, where did he get that from?"
Before his release, Mr Abdel Ghani called the channel, saying he was speaking from the chief prosecutor's office in Cairo.
He denied the charge of "propagating false news".
Mr Abdel Ghani, who worked previously for the BBC's Arabic service and has reported for al-Jazeera from Cairo since 1997, said he was bundled into a van in Dahab and driven away.
"I was treated in a very inhumane way," he said.
A member of the Egyptian journalists' union, Gamal Fahmy, told AFP news agency: "We consider the arrest of the head of the al-Jazeera bureau to be an attack on press freedom in Egypt."
Al-Jazeera is watched by millions of Arab viewers but its reporters have been barred by a number of countries in the region.
Egypt has blamed local Bedouins linked to an Islamic militant group for the Dahab bombings.
In a separate development on Thursday, Egyptian Prime Minister Ahmed Nazif has said there are increasing indications that attack on Dahab was carried out by suicide bombers.
Mr Nazif told the BBC that the authorities were examining the remains of three bodies, which, he said, might be those of suicide bombers.
The prime minister also accused radical Islamists within the local Bedouin population of having carried out a series of bombings in the Sinai peninsula over the past 18 months.
He said the Bedouins of Sinai had been radicalised by unidentified people within Egypt - and that there was no evidence of financing or direct orders coming from militant organisations abroad, such as al-Qaeda.