U.N. Secretary-General Ban Ki-moon has told Syrian President Bashar al-Assad that he is alarmed at reports of excessive use of force by government security forces against citizens and continued widespread violations of human rights.
Ban spoke by telephone Wednesday with Assad, who said military and police operations had stopped.
A spokesman for the U.N. chief said Ban also continued his calls for an independent investigation into the violence, and for Syria to cooperate with the U.N.'s human rights office.
The U.N. Security Council is set to hear Thursday from U.N. human rights chief Navi Pillay, who is expected to call for the Council to refer Syria to the International Criminal Court.
The U.N. Human Rights Council said Thursday it will hold a special session on Monday to examine the violence in Syria, following a request from 24 of its members. Those calling for the session included all four Arab nations on the council - Jordan, Kuwait, Qatar and Saudi Arabia.
Ban's spokesman said Assad also pledged to carry out several reforms in the coming months, including revising the country's constitution and holding parliamentary elections.
Meanwhile, Western media say the White House is preparing to call for Assad to step down. The move could come as early as Thursday, and may also include plans for new sanctions against Syria.
The United States has criticized Assad saying he has lost legitimacy, as he faces growing international pressure to end the violent crackdown against dissent.
Activists said Syrian security forces detained hundreds of people Wednesday in the besieged port city of Latakia, where at least 35 people have been killed during the past week.
The London-based Syrian rights group Syrian Observatory for Human Rights said that more than 700 troops raided homes in Latakia's southern al-Raml district, arresting people on lists.
Activists also said forces loyal to Assad killed nine people in the central city of Homs, including two protesters shot dead in front of a mosque after nightly Ramadan prayers.
Latakia's al-Raml is home to a crowded Palestinian refugee camp where many low-income Syrians also live. U.N. officials say as many as 10,000 residents fled the neighborhood during Syria's four-day operation to crush dissent in the city.
The United Nations Relief and Works Agency said Wednesday it has determined the whereabouts of about 2,000 of the displaced people and is providing them with aid.
Turkish Prime Minister Recep Tayyip Erdogan Wednesday compared the situation in Syria with that in Libya, noting that Assad's government continues to kill civilians despite repeated diplomatic intervention. Separately, Turkish Foreign Minister Ahmet Davutoglu called for "the bloodshed" to stop during a joint news conference with his Jordanian counterpart.
The U.S. State Department also said Wednesday the United States is restricting the travel of Syria's ambassador to the U.S. as well as other embassy personnel. A spokesman said the officials must get permission to travel outside the Washington metropolitan area, and that the move is in response to a similar ban on U.S. personnel enacted by Syria last month.
Meanwhile, the United Nations said it is withdrawing its non-essential personnel from Syria.
Rights groups and activists say at least 1,800 civilians have been killed since the start of the government's crackdown in mid-March.
Some information for this report was provided by AP and Reuters.