President Tito's doctors issued another gloomy report on his health yesterday after a weekend leg operation that failed to correct his vascular ailment.

The medical bulletin coincided with noticeable security reinforcement in the Yugoslav capital and an emergency session to the country's Communist leadership. Officials said the armed forces were also put on alert, with leaves either prestricted or canceled, reportedly in response to a military alert in the neighboring Soviet-bloc countries of Hungary and Bulgaria.

Intelligence sources said that Soviet-bloc alert was linked to the Soviet invasion of Afghanistan.

Prime Minister Veselin Djuranovic canceled his annual reception for foreign ambassadors here to attend the leadership meeting. An official statement said the party and government leaders "approved of all measures" taken relating to the health of the 87-year-old Tito.

Tito underwent an operation to remove a blood clot in a main artery and doctors provided him with an artificial vessel. Although the doctors said that Tito was feeling "better in relation to the previous day," they said that "the condition of the operated leg is unchanged."

Among messages Tito received from foreign leaders wishing him a swift recovery were cables from President Carter and Chinese leaders Hua Guofeng.