A tree is blown down in Chetumal by Hurricane Dean, August 21, 2007. (Xinhua/Reuters Photo)

MEXICO CITY, August 21 (Xinhua) -- Mexico's National Weather Forecast Service (SMN) called the inhabitants of southeastern Mexico on Tuesday to remain on alert due to Dean's pass.

Hurricane Dean was downgraded from category-5 to category-3, SMN's general coordinator Michel Rosengaus told the press.

But Dean is still dangerous even though it lost strength, Rosengaus said.

President Felipe Calderon said "No human losses have been reported until now."

At 06:00 local hours (11:00 GMT) Hurricane Dean hit the southeastern Mexican states of Campeche, Quintana Roo, and Yucatan Peninsula on Tuesday with sustained winds of 250 km per hour, flooding streets, toppling trees and blowing roofs off houses before heading for oil platforms in the Gulf of Mexico.

The civilian protection officials did not report victims in any of the three states of the Yucatan Peninsula, but they foresee floods caused by the heavy rainfalls in the region.

Dean's heavy winds tumbled trees, telephone and electricity lines, roofs, among other things in Chetumal, Quintana Roo's capital, 1,100 kms east of Mexico City.

Thousands of national and foreign tourists had left Cancun beach resort prior to Dean's arrival, while thousands of other people were transferred to temporary shelters.

The SMN said that Dean is moving at an average of 32 kms per hour and will leave Mexican territory in the forthcoming hours.

Dean's winds fluctuate between 205 and 250 kms per hour and cause rainfalls in Yucatan's Peninsula , Rengaus said.

The SMN said Dean will cause rainfalls in the states of Veracruz and Tamaulipas, both in the Gulf of Mexico region.

The strong winds caused by hurricane Dean have caused strong waves in the states of the Yucatan Peninsula (Campeche, Yucatan and Quintana Roo).

Tamaulipas' officials suspended navigation in shrimp boats to avoid casualties.

Hurricane Dean caused problems in many Caribbean countries, it also hit southeastern Mexico and is heading towards southeastern United States.