A statement sent by al-Aqsa Martyrs Brigades to Aljazeera's office in Gaza on Thursday said the group was not behind the kidnapping.
AFP, however, quoted an anonymous caller identifying himself as a member of a group of supporters of Massud Ayyad, a senior member of the Al-Aqsa Martyrs Brigades assassinated by Israeli forces at the beginning of the second intifada, as saying: "Today we kidnapped two Israeli soldiers in the Nablus region and they are at present in our hands."
Israel has refused to comment on the reports.
The Israeli occupation army said it had earlier staged a military offensive on the centre of Nablus, which is the main city in the northern West Bank.
Eight jeeps took part in the military operation during which Israeli occupation forces opened fire at a group of youths, who responded by throwing stones, witnesses said.
There were no reports of casualties yet.
Eight Israeli military jeeps took
part in the offensive in Nablus
Reuters also reported quoting a Palestinian security source that an Israeli military vehicle had been found abandoned in the Balata refugee camp, an area of Nablus city.
It showed no signs of having been damaged in any fighting.
"They are missing until now. The investigation is continuing to find out where they got to," the source said.
Meanwhile, Aljazeera has learnt that the Central Committee of the Fatah Movement will meet in Amman on Thursday.
The meeting will be attended by Palestinian President Mahmoud Abbas and head of Fatah, Faruq Qaddumi.
The meeting of the 16-member Fatah Central Committee is the first in almost 10 years.
It takes place in Jordan so that the largest possible number of committee members can attend, including exiled leaders who refuse to deal with Israel.
Top on the agenda is "reforming and re-organising Fatah's committee through elections and holding a wider conference to discuss these issues," Nabil Shaath, the Palestinian Authority information minister, said.
Salim Zaanoun, speaker of the Palestinian National Council, said committee members will also discuss, in the next two days, the relationship between the Foreign Ministry and the Palestinian Liberation Organisation's political office, headed by Qaddumi.
Abbas's political rival
Qaddumi is the nominal leader of the ruling Fatah party.
Faruq Qaddumi and Abbas met
behind closed doors in Amman
He is seen as the strongest political rival to Abbas. Tensions between Abbas and Qaddumi have flared in recent months.
According to Palestinian legislator Azmi Shuaibi, Abbas intended to create a symbolic post to sideline Qaddumi who has chosen to remain in exile.
Abbas and Qaddumi met behind closed doors in Amman late on Wednesday.
Palestinian officials declined comment, but said the discussions were "positive".
Shaath dismissed talk of differences. "Every member of the central committee attended the meetings, so there is no tension, whatsoever," he said.
"The meetings were not held to discuss the differences in Fatah, but to agree upon a new line in dealing with all the issues, including Israel's unilateral Gaza withdrawal, the barrier, the blockade and Jerusalem's judaization," he said.
"We hope to solve the problem and create comprehensive ties between both departments," Zaanoun said, referring to the Palestinian Foreign Ministry and Qaddumi's politburo.
Zaanoun said that the issue of appointing a Palestinian vice-president would not be tackled during the talks.
"It must be discussed in a joint meeting between the Palestinian National Council and the Palestinian Central Council."
Jordan's senior officials, including King Abdullah II, his prime minister Adnan Badran and Royal Court adviser and former foreign minister Marwan Muasher visited the Palestinians during their meetings.