President Viktor Yushchenko hailed a major step in Ukraine's drive to shake off its post-communist tag and move closer to the West, as the WTO formally ended 14 years of negotiations and invited Ukraine to join the global trading community.

The Ukrainian leader also on Tuesday reaffirmed his goal of steering Ukraine into NATO, which has caused friction with neighbor Russia and angry protests at home. But he said the ex-Soviet state would do its utmost to help Russia also accede to the WTO, where the two countries would be able to find common rules and a neutral arbiter to deal with their sometimes tense trade relations over gas and other issues.

"We have had deep conviction and commitment to integrate the Ukrainian economy into the World Trade Organization," Yushchenko said after signing accession terms with WTO chief Pascal Lamy. "Today is a historic event."

Yushchenko - whose "Orange Revolution" partner Yulia Tymoshenko recently returned as prime minister - cited expert studies that said WTO entry could mean a 10 percent jump in Ukrainian consumption and an additional 1.7 percent boost to the country's already impressive growth rate, which was around 7.3 percent last year.

He said the studies indicate foreign investment could increase by 50 percent to $10.5 billion annually, and that the "new dynamics for the economy" would significantly aid Ukraine's chemicals and metals sectors.

The chemical industry could hike its production by 21 percent, exports by 30 percent and employment by 17 percent as a result of fewer barriers to trade, now that Ukraine will be given the "most favored nation" status used by the current 151 WTO nations in trading with each other, Yushchenko said. Metals production could rise 22 percent, exports 26 percent and employment 19 percent.

"Today's step means quite a lot for the country, for the world community and for the average citizen in the Ukraine," Yushchenko said, adding that Ukraine's parliament might be able to ratify the deal by the end of February.

Earlier Tuesday, Ukraine's messy politics plunged further into chaos in Kyiv, when protests and scuffles in parliament prevented Yushchenko from delivering his annual state of the union speech.

The work of the country's deeply divided parliament has been virtually paralyzed for several weeks, after pro-Western leaders took a key step toward seeking NATO membership. The Moscow-friendly opposition Party of Regions responded by resorting to the tactic of blocking the rostrum, thus preventing voting and discussion of bills.

Yushchenko said Ukraine needed to move beyond old perceptions of NATO as an aggressive military alliance.

"I'm trying to ask the whole nation: Which model should the country adopt in order to live in peace and stability for centuries ahead?" he told reporters through an interpreter. "We don't have many choices to choose from.

"We can go back to yesterday, but not one post-communist country has gone down that path. They all embraced the collective defense system. Therefore, I'm asking myself why Ukraine cannot make this choice in its national defense interests."

Yushchenko has had chilly relations with the Kremlin since 2004, when Moscow gave strong support to Yushchenko's rival Viktor Yanukovych in his fraud-riddled run for the presidency, which set off the massive Orange Revolution demonstrations. Many observers also suspected Moscow in the massive dioxin poisoning of Yushchenko that left his face pockmarked and discolored.

Yushchenko has since clashed with Russian President Vladimir Putin over gas prices and other issues. Moscow temporarily cut off gas supplies to Ukraine two winters ago - a shutdown also felt in Western Europe - in a move widely seen as punishment for Ukraine's pro-Western policies.

Yushchenko, however, said Ukraine would not unfairly use its new position inside the WTO to damage Russia's 15-year accession bid, which must be accepted by all members of the trade body.

Russia in the WTO would mean less hurdles for Ukrainian exports of a number of commodities, including spirits, oil, sugar, raw materials and equipment, Yushchenko said. It might also help eat into a bilateral trade deficit of $6 billion with Russia, which some Ukrainian exporters are blaming on unfair Russian trade barriers.

"Ukraine is one of a few countries which would like to see trade relations with Russia liberalized to a maximum extent," he said. "We are sincere partners ... We will do everything to eоsure that Russia joins this club as soon as possible."