In a boost to Gaza's Hamas government, the Gulf state of Qatar said on Sunday it opened the first diplomatic office in the isolated territory since the Islamic military group took power five years ago.

Qatari officials said the office is not a formal embassy. Instead, it will oversee hundreds of millions of dollars in aid projects Qatar is funding.

Nonetheless, it is headed by an ambassador and marks a key stamp of legitimacy for Hamas, whose takeover of Gaza in 2007 has never been internationally recognized.

Hamas' rival, President Mahmoud Abbas, who lives in the West Bank, is seen internationally as the Palestinian leader.

Abbas has long had rocky relations with Qatar, whose Al-Jazeera satellite channel is often critical of the Palestinian leader. Qatar often frequently hosts Hamas leaders.