An Egyptian labor ministry official and three trade union activists were kidnapped in the Sinai on Tuesday, the ministry said, according to AFP.
Local police were investigating whether Sinai terrorists were behind the abduction, the report said.
Meanwhile in Cairo, assailants threw a bomb and opened fire on a small traffic police station without causing casualties, security officials told the news agency.
It was the latest in a string of militant attacks on security forces following the overthrow of Islamist president Mohammed Morsi in July.
Much of the violence has taken place in Sinai, where the officials were abducted while en route to a conference in the southern resort town of Sharm El-Sheikh.
Police found their abandoned car near the resort, labor ministry spokesman Alaa el-Din Mohamed told AFP.
An interior ministry official said police were investigating the kidnappings.
The Sinai has become increasingly lawless since the fall of former president Hosni Mubarak in February 2011, and the terror attacks have only increased since the removal of his successor, Mohammed Morsi.
The Egyptian armed forces have launched large scale military operations against terrorists in Sinai in an attempt to suppress the insurgency. The terror groups have hit back - a torrent of attacks by gangs of Al Qaeda-inspired Islamic terrorists have killed many Egyptian soldiers and policemen since Morsi's overthrow.
In September, Egypt’s Interior Minister survived an assassination attempt. The attempted assassination occurred as a car bomb ripped through the his convoy as he was leaving home for work.
Tensions in Egypt have increased in recent weeks, especially after the interim government blacklisted Morsi’s Muslim Brotherhood as a terrorist organization and launched a wide-ranging crackdown on the group.
In response to the blacklist, the Muslim Brotherhood has filed a complaint with the International Criminal Court (ICC) against the military-ruled government.