U.S. officials say Iraq's poison gas attacks on Iranian forces and Kurdish rebels could encourage other countries to follow Baghdad's lead, eroding a worldwide inhibition against use of chemical weapons.

Official U.S. arms experts say the number of countries that have acquired chemical weapons or are seeking them is expanding alarmingly - from perhaps 10 five years ago to about 20 today - and that Iraq's example has made chemical attacks more likely elsewhere."For a long while, the (chemical weapons) genie had been kept in the bottle, but it's out," Secretary of State George Shultz said in a speech on Friday, urging international pressure against Iraq.

His spokesman Charles Redman elaborated in a statement condemning Iraq, which has denied U.S. accusations that it gassed Kurdish dissidents.

Redman told reporters that Iraq was "raising the barrier to the use of chemical weapons. The world community has to be very alert. There seems to be a more general willingness to try to use this kind of weaponry."

He said Washington was convinced that Iran and Syria had acquired chemical arms and that virulently anti-U.S. Libya, which Washington has branded a terrorist state, was seeking its own poison gas arsenal.

Other American officials have told Congress the Peoples Republic of China, Taiwan, North Korea, Vietnam and Burma were seeking chemical weapons and that the first three were also seeking a stockpile of deadly biological weapons.

The United States, which has frequently condemned Iraq for chemical weapons attacks in its war with Iran, last week accused it of "abhorrent" poison gas strikes against Iraqi Kurds seeking political autonomy.

Iraq - which launched a major offensive against rebel Kurds in northern Iraq on July 19, the day after Iran accepted a U.N. ceasefire resolution in the Persian Gulf war - has repeatedly denied using gas against the Kurds. An estimated 100,000 Kurds have fled into Turkey.

U.S. officials insist the evidence that Iraq used poison gas against the Kurds is conclusive and shows how launching chemical weapons attacks in one situation can erode the inhibitions against using them elsewhere.