The Security Council is expected to deploy 250 monitors to Syria on Wednesday when it considers the issue.
The United Nations Security Council is expected to authorize deploying a full mission of 250 monitors to Syria after it takes up the issue Wednesday, but Secretary-General Ban Ki-moon questioned whether even that number would be sufficient.
"I think this is not enough, considering the current situation and considering the vastness of the country, and that is why we need very efficient mobility of our observer mission," he said Tuesday.
He said he had discussed with European Union leaders whether the EU could provide helicopters and airplanes for that mobility.
Six members of a U.N. mission to monitor implementation of a peace plan began setting up headquarters inSyria on Monday, and 25 additional observers are expected to arrive in Damascus, the capital, in coming days.
Ban said U.N. military action was not under consideration.
"At this time, the situation is so complicated that we are not contemplating any ... introduction of military protection," he said. "This is the responsibility of the Syrian authorities."
Violence has persisted in parts of Syria since a cease-fire began Thursday, leading some to declare the peace plan a failure.
Shelling continued in the battered city of Homs, and the government has intensified an offensive in the northwestern province of Idlib, activists say. Reports Tuesday said almost 70 people had been killed, most of them in Idlib, in tank and helicopter attacks over the last two days.
One activist, Khalid Mahmoud Qbiesho, was reported killed in Idlib when a tank ran over him, according to the Local Coordination Committees, an antigovernment group. Others were killed execution-style, activists said.
Meanwhile, in Paris, representatives of 60 governments belonging to the group Friends of the Syrian People met to reinforce sanctions imposed on the Syrian regime amid the 13-month uprising, which the U.N. estimates has taken more than 9,000 lives.
French Foreign Minister Alain Juppe said the sanctions had depleted Syrian government financial reserves by half, The Associated Press reported. Juppe said the regime of President Bashar Assad was trying to maneuver around the sanctions and that "we must respond to these maneuvers."
"Our meeting is in itself a message," Juppe said. "The Syrian regime must understand that it cannot continue its repression with impunity and refuse the political transition laid out" by the peace plan, which was presented by U.N. and Arab League special envoy Kofi Annan and accepted by the Syrian government.