DACCA, Pakistan, Oct. 5—Diplomatic sources reported today that guerrilla divers damaged a Greek tanker with explosives in the East Pakistani port of Chittagong Friday night in a continuing campaign to hamper shipping.

The damaged ship, the Avlos, was listing at the dock and apparently was being pumped to keep her from sinking, a witness said. There was speculation that the Avlos had been selected partly for the purpose of blocking the dock area.

Since Aug. 16, divers have attacked and damaged or sunk at least a dozen vessels in East Pakistani ports. On Aug. 16 alone there were attacks on ships in Chittagong, Narayanganj, Chalna and Chandpur. In attacks on Sept. 19 and 26, five ships were damaged at Chalna.

One of the more heavily damaged ships was the British owned Cheviot, a 13,082‐ton vessel. Mines blew holes in both sides of the Cheviot.

Trade sources here report that several shipping lines are considering eliminating Chalna from their ports of call.

Pakistani authorities charge that India has trained a corps of underwater demolition experts to prey on shipping.

Government authorities here announced last week that they killed 10 frogmen and captured 3 others.

Pakistani officials said the frogmen had been trained in India to attack ships in Chalna and Chittagong and had been supplied with limpet mines—devices that adhere to ship hulls below the waterline. A security cordon around Chalna reportedly has been established by the Government to a distance of 12 miles from the port.

Despite the precautions it is apparent that the danger posed by guerrilla frogmen has not been eliminated. East Pakistan is highly dependent on water traffic for supplies from abroad and for transportation within the province.

Pakistan charges that the guerrillas are deliberately sabotaging efforts by various nations to ship relief supplies, notably food grains, to the strife‐torn province.

Bengali separatist rebels charge on their clandestine transmitter, Radio Bangla Desh, that most water traffic to and in East Pakistan is employed for military purposes and therefore a proper target. A large part of East Pakistan is a flood plain with relatively few roads or railroads. Since last March, when the army moved against the East Pakistani separatist movement, large numbers of bridges and culverts have been destroyed by the guerrillas.

When a bridge is blown up a ferry is generally put into operation, at least for the use of the army. On the key road eastward from the capital of Dacca to Comilla on the Indian border, for example, there were three ferries six weeks ago. Now, so many bridges have been destroyed or damaged that a large part of the trip is by water. In some parts of the country, civilians are banned from ferry crossings, and most if not all motor launches have been commandeered by the army. The population in such areas is dependent for travel on hand‐poled boats.