The prime minister of Thailand pledged Sunday to end the nation’s ivory trade, responding to growing calls from international wildlife groups desperate to stop the slaughter of African elephants.

In a speech at the opening of the Convention on International Trade in Endangered Species conference in Bangkok, the prime minister, Yingluck Shinawatra, promised to amend the kingdom’s laws, which critics say include loopholes that have allowed smugglers to ferry African tusks to Thai markets and onward, often to China, the world’s top destination for illegal ivory. Thailand is believed to be the second-biggest market for illicit elephant tusks.

“We will work towards amending the national legislation with the goal of putting an end to ivory trade and to be in line with international norms,” Ms. Yingluck said. “This will help protect all forms of elephants, including Thailand’s wild and domestic elephants and those from Africa.”

The announcement, which pleased environmentalists, places additional pressure on China to halt its legal ivory trade, a thriving industry that experts say has helped fuel the highest rate of African elephant poaching in decades.

Since the beginning of 2012, conservationists say, more than 32,000 elephants have been killed by poachers. Although some of the ivory ends up in Thailand, much of it is smuggled to China, where it is carved into the figurines, chopsticks and other trinkets coveted by that country’s newly affluent consumers.

Animal rights groups have accused the Chinese government of failing to stem the surge in illegal ivory, a charge that Beijing denies.

Changing Thai law, which currently violates international rules set by the convention, would also remove the threat of trade sanctions against Thailand that have been sought by conservation groups.

Ms. Yingluck did not give a timeline for amending the legislation, a point of concern for conservationists, who note that Thailand has been promising to change its laws for several years, to little effect.

“I’m not opening the Champagne yet,” said Mary Rice, executive director of the independent Environmental Investigation Agency. Ms. Rice, who is attending the conference, also criticized the ambiguity of Ms. Yingluck’s promise, which did little to clarify whether the proposed ban would halt both international trade and domestic sales.

Thai law currently allows for the sale of ivory from domesticated local elephants, one of the loopholes that critics say has given smugglers ample legal cover for laundering poached African ivory into Thailand and beyond.

Before the conference, conservation groups, including the World Wildlife Fund and the trade monitoring agency Traffic, urged the convention to punish Thailand, along with Nigeria and the Democratic Republic of Congo, for not doing enough to stem illegal ivory trading.

But other groups cited the absence of China from this list as proof that politics had contaminated efforts to save Africa’s herds. “The whole issue of what’s happening in China is the elephant in the room,” Ms. Rice said.