of the Duck Hook plan within three days under the operational title Pocket Money. At precisely 09:00 (local time) on 9 May, six US Navy A-7 Corsair IIs and three A-6 Intruders from the USS Coral Sea flew into Haiphong harbor and dropped thirty-six Mark-52 and Mark-55 naval mines into its waters. They were protected from attacks by Vietnam People's Air Force (VPAF) MiG fighter aircraft by the guided-missile cruisers and , with several destroyers including the guided-missile destroyer launching Operation Custom Tailor and by supporting flights of F-4 Phantoms. The reason for the precise timing of the strike became apparent when Nixon simultaneously delivered a televised speech explaining the escalation to the American people: "The only way to stop the killing is to take the weapons of war out of the hands of the international outlaws of North Vietnam.". The mines were activated five days after their delivery to allow any vessels then in port to escape without damage. Over the next three days other US carrier-based aircraft laid 11,000 more mines into North Vietnam's secondary harbors, blockading all maritime commerce for the country. Before and during Pocket Money, Nixon and Kissinger had worried about the Soviet and Chinese reaction to the escalation. Hours before Nixon's speech announcing the mining, Kissinger had delivered a letter to Soviet ambassador Anatoly Dobrynin which outlined the U.S. plan, but which also made clear Nixon's willingness to proceed with the summit. The next day, Nixon shook the hand of Soviet Foreign Trade Minister Nikolai Patolichev at the White House. Although Moscow and Beijing publicly denounced the American operation, they were not willing to jeopardize their thawing relationship with the U.S. and Hanoi's requests for support and aid from its socialist allies met with only cool responses. Going north Operation Linebacker, the code name for the new interdiction campaign, would have four objectives: to isolate North Vietnam from its sources of supply by destroying railroad bridges and rolling stock in and around Hanoi and north-eastwards toward the Chinese frontier; the targeting of primary storage areas and marshalling yards; to destroy storage and transshipment points and to eliminate (or at least damage) the North's air defense system. With nearly 85 percent of North Vietnam's imports (which arrived by sea) blocked by Pocket Money, the administration and the Pentagon believed that this would cut its final lines of communication with its socialist allies. China alone shipped