Egypt's Foreign Minister Mohammed Amr has warned that arming rebel fighters in Syria would lead to a civil war, his ministry said on Wednesday.

Arming the ill-equipped rebels, mainly Syrian army defectors, would "lead to an escalation in the military conflict and spark a civil war in Syria", Amr said, according to a statement issued by his ministry.

Two explosions on Monday hit a pipeline which supplies Egyptian gas to Israel and Jordan, marking the 13th such attack in just over a year, security officials said.

Six gunmen in an unmarked vehicle set explosives in two different parts of the pipeline, about 15 meters (yards) apart, one official told Agence France Presse.

The United States remains committed to strong ties with Egypt, a U.S. official said Saturday, after tensions over the treatment of U.S. activists who had been barred from leaving Cairo.

"We have all been focused over these past few weeks on the NGO issue, and it is a matter of serious continuing concern for the United States," State Department spokeswoman Victoria Nuland said in a statement.

Egypt's parliament is to probe and "hold accountable" anyone who intervened to allow foreign activists on trial to leave the country, the house speaker said on Saturday.

Saad al-Katatni said parliament would summon officials to explain the decision and "hold accountable those responsible for this crime, which represented a blatant intervention in the affairs of Egypt's judiciary."

A Spanish court has agreed to extradite a fugitive Egyptian businessman who is on trial for corruption along with ousted president Hosni Mubarak, the Egyptian foreign ministry said on Friday.

Spain has informed the Egyptian ambassador in Madrid that a Spanish court "has agreed to hand Hussein Salem and his son Khaled to Egypt," spokesman Amr Roshdy said in a statement.

Egyptian newspapers angrily accused the ruling military on Friday of caving in to U.S. pressure to allow foreign NGO workers, including a number of Americans, to escape trial on charges of illegal funding.

One of them also accused the Supreme Council of the Armed Forces (SCAF) of trashing the concept of an independent judiciary, insinuating that it had strong-armed the courts into lifting a travel ban on the suspects.

Seven Americans on trial over charges their pro-democracy groups fomented unrest have flown out of Egypt after the U.S. posted nearly $5 million in bail for them and nine others who managed to leave before a travel ban was imposed.

Thursday's departure of the seven eased a deep diplomatic crisis between the U.S. and Egypt that had been building for two months, following a crackdown on pro-democracy and human rights groups by the Egyptian government.

American and other foreign democracy activists on trial in Egypt flew out of Cairo airport on Thursday, airport officials said, a day after the judiciary lifted a travel ban on them.

Their departure is expected to ease tensions with Washington, which had urged Egypt's military rulers to resolve the case which American officials had suggested could imperil U.S. aid to its key Middle Eastern ally.

Egypt has lifted a travel ban on democracy activists, including Americans, on trial for receiving illicit foreign funding in a case that has tested relations with Washington, prosecution sources said on Wednesday.

U.S. Secretary of State Hillary Clinton quickly welcomed the news but said Washington was still awaiting confirmation.

Egypt will vote on May 23 and 24 to elect its first president since a popular uprising overthrew Hosni Mubarak a year ago, the head of the elections committee said on Wednesday.

Farouq Sultan told journalists expatriates will be allowed to vote from May 11 to May 17 and that any run-off will be held on June 16 and 17.