Mexico's president has demanded changes to a bill passed by Congress that would see some drugs decriminalised, a day after saying he would sign it into law.
Some are accusing the president of bowing to US pressure
The bill, as it stands, would legalise possession of small amounts of cocaine, marijuana and heroin for personal use.
President Vicente Fox has returned the measure to Congress, saying it should make clear that possessing and using drugs will remain a criminal offence.
Mr Fox has been accused in the Mexican media of bowing to US pressure.
US officials had voiced concern that more lenient policies in Mexico could lead to a wave of drugs-related tourism across the border.
San Diego Mayor Jerry Sanders - who had earlier said he was "appalled" - welcomed Mr Fox's decision to amend the bill.
"I'm glad that he has listened to the many voices opposing the bill and made changes that will make good enforcement and not legalise drugs," Mr Sanders said.
"We have been a partner with Mexico in fighting against illegal drugs, and this will only help in the long-term in that relationship."
Earlier on Wednesday, US embassy spokesperson Judith Bryan said US officials had "urged Mexican representatives to review the legislation urgently, to avoid the perception that drug-use would be tolerated in Mexico, and to prevent drug tourism".
The legislation passed by Congress was initially designed by the president's office and introduced by his National Action Party. Officials have said the proposal was then changed by legislators.
In a statement, Mr Fox did not refer to the US criticism but acknowledged the bill had stirred up controversy.
"With sensitivity toward the opinions expressed by various sectors of society, the administration has decided to suggest changes to the content of the bill," he said.