Rescue workers search for people trapped beneath the rubble of collapsed buildings on Thursday after a pair of deadly earthquakes wreaked havoc in and around Caracas, the capital of Venezuela. At least 164 people have died and 971 were injured after the two powerful earthquakes jolted the South American country late Wednesday. ARIANA CUBILLOS/AP

Two powerful earthquakes struck Venezuela on Wednesday, killing at least 164 people and injuring 971 after dozens of buildings collapsed into piles of shattered concrete and steel in and around Caracas, the nation's capital.

China expressed its condolences to Venezuela on Thursday after the earthquakes, saying that it stands ready to provide assistance based on the South American country's needs.

A magnitude 7.2 earthquake hit about 160 kilometers west of Caracas, followed less than a minute later by a magnitude 7.5 tremor, according to the United States Geological Survey. The twin quakes, the country's strongest in 126 years, hit when many Venezuelans were at home during a public holiday.

The US Pacific Tsunami Warning Center issued several tsunami alerts that were quickly lifted.

Delcy Rodriguez, the acting president of Venezuela, said the coastal state of La Guaira in northern Venezuela was hit the hardest, describing it as a "disaster zone" where dozens of buildings had collapsed entirely.

"La Guaira state is a true tragedy," Rodriguez said on Venezuelan state television.

Municipal police officers evacuate an injured victim from a collapsed building following the powerful quakes in Caracas on Wednesday. The quakes were among the strongest to strike Venezuela in more than a century and could be felt throughout the region. JUAN BARRETO/AFP

Rescue operations were underway as the country declared a state of emergency following the strong earthquakes, with the number of casualties and extent of damage expected to rise.

Foreign Ministry spokesman Guo Jiakun said at a regular news briefing that China "has noted reports of the earthquakes in Venezuela and extends its sincere sympathies to the Venezuelan government and the people affected by the disaster". No Chinese casualties had been reported so far, he said.

"We believe that, under the leadership of the Venezuelan government, the Venezuelan people will overcome the disaster and rebuild their homes as soon as possible," Guo said. "China stands ready to provide assistance within its capacity and in an appropriate manner based on Venezuela's needs."

While Venezuela sits near multiple fault lines, its position straddling the South American and Caribbean plates makes strong earthquakes much less common than in other parts of Latin America.

Rodriguez appealed to businesses to make heavy construction equipment available for rescue operations, adding that search and rescue teams certified by the United Nations were on their way to Venezuela to assist.

She said authorities were shifting rescue teams from other parts of the country to La Guaira, which is north of Caracas on the coast, adding that officials were trying to make the most of daylight hours to speed up efforts to rescue people believed to still be trapped under the rubble.

The acting president said the government was creating a $200 million reconstruction fund for hospitals and homes damaged by the earthquakes, and the nation's economy and finance minister was instructed to oversee the effort.

Television broadcasts on Thursday showed rescue workers using power tools to work their way into piles of rubble. Many people searching for the missing appeared to be regular citizens rather than professionals. Collapsed buildings, toppled electrical poles and debris blocked streets.

During the quakes, people ran from swaying buildings in Caracas, and many were visibly shocked when they turned back to see destroyed walls that left furniture visible from the street. Columns of dust rose in two typically busy neighborhoods in the capital.

Parts of the capital lost power and cellphone coverage, and the earthquakes damaged and closed Simon Bolivar International Airport, the country's main airport, Rodriguez said. In Caracas, subway service was suspended and natural gas shut off, she said.

Schools canceled classes for several days, and the Ministry of Education said some school buildings would be used as shelters and donation centers. Emergency workers scrambled over the debris of collapsed buildings in Caracas as night fell, while distraught relatives sought help for loved ones feared trapped.

Dazed survivors were taken away, some on stretchers.

The lack of cellphone coverage in parts of Venezuela deepened the distress of many families, particularly those among the more than 7.7 million people who have left the country during its protracted crisis and who struggled to reach relatives inside the country.

Leaders from countries including El Salvador, the Dominican Republic, Brazil and Spain offered support and sympathy. The US State Department said it was in touch with Venezuelan authorities and mobilizing assistance.